national energy efficient building project (neebp) phase 2...

National Energy Efficient Building Project (NEEBP)

Phase 2 Project 3

Improving Compliance and Consistency in the Application of the National Construction Code Energy Performance

Requirements to Class 1 and 10 Additions and Alterations

The NEEBP is led by the Government of South Australia’s Department of State Development and is co-funded by all Australian states and territories through the Council of Australian Governments (COAG) Energy Council. Date: March 2016

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Disclaimers The findings of this report do not represent the views of the Commonwealth Government, State and Territory jurisdictions nor the South Australian government as Project Manager. Rather they represent the views of independent consultants Sustainability House based on evidence collected throughout the course of this study. The material in this document is made available for information only and on the understanding that the Commonwealth and the state and territory governments (the Participating Bodies) are not providing professional advice, nor indicating a commitment by the Participating Bodies to a particular course of action. While reasonable efforts have been made to ensure the information is accurate, correct and reliable, the Participating Bodies, and all persons acting on behalf of the Participating Bodies preparing this publication, accept no liability for the accuracy of, or inferences from, the material contained in this publication, and expressly disclaim liability for any person’s loss arising directly or indirectly from the use of, inferences drawn, deductions made, or acts on in reliance on this document. The material in this document may include the views or recommendations of third parties, which do not necessarily reflect the views of the Participating Bodies, or indicate their commitment to a particular course of action.

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Glossary of terms and acronyms Addition Extension of a dwelling’s existing floor area that involves new building work subject to a building application and is approved by a building certifier. Alteration A change to the external building fabric of an existing dwelling that is subject to a building application and is approved by a building certifier. For the purpose of this report, it does not include minor alterations (i.e. That do not require a building application such as general repairs or maintenance to the existing dwelling). BAB Building Appeals Board (VIC) BASIX Building Sustainability Index (NSW) BCA Building Code of Australia Class 1 NCC building classification for one or more building which in association constitute;

● Class 1a - single dwelling being i) a detached house, or ii) one of a group of two or more attached dwelling, each being a building, separated by a fire-resisting wall, including a row house, terrace house, town house or villa unit; or

● Class 1b - a boarding house, guest house, hostel or the like with a total floor area not exceeding 300 m² in which no more than 12 persons would ordinarily be resident.

● Class 10 - NCC definition for Class 10 buildings and structures covers; - Class 10a - a private garage, carport, shed or the like, - Class 10b - a structure such as a fence, mast, antenna, retaining wall, swimming pool, or the like, and - Class 10c - a private bushfire shelter.

For the purpose of this review Class 10 only refers to Class 10a that is attached to a Class 1 dwelling. COAG Council of Australian Governments CPD Continuing Professional Development DSD Department of State Development DtS Deemed to Satisfy compliance methods (Elemental or Energy Rating) NatHERS Nationwide House Energy Rating Scheme NEEBP National Energy Efficient Buildings Project NCC National Construction Code NT Northern Territory NSW New South Wales QLD Queensland Relocation Moving an existing dwelling from one location to another Renovation Is used within this report to encompass an alteration, addition or relocation where new building work is subject to a building application and is approved by a building certifier. SA South Australia SHGC Solar Heat Gain Coefficient of glazing TAS Tasmania

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U-value Overall heat transfer coefficient of window systems (for glazing and its frame) VIC Victoria WA Western Australia

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Contents Disclaimers ....................................................................................................................................... 2

Glossary of terms and acronyms ...................................................................................................... 3

Executive Summary .......................................................................................................................... 7

Background ................................................................................................................................... 7

Objectives ..................................................................................................................................... 7

Approach ....................................................................................................................................... 7

Findings ........................................................................................................................................ 8

Recommendations ........................................................................................................................ 9

Stakeholder benefits .................................................................................................................... 10

1. Introduction .............................................................................................................................. 11

1.1 Background ........................................................................................................................... 11

1.2 What Are Alterations & Additions? ......................................................................................... 12

1.3 The National Construction Code ............................................................................................ 12

Variation Management and Code Consolidation ...................................................................... 12

1.4 Renovations of the Existing Housing Stock ........................................................................... 13

1.5 Potential benefits beyond energy efficiency ........................................................................... 13

1.6 Research approach - Identifying the problem ........................................................................ 13

2. Review of Jurisdictional requirements and regulations ............................................................... 14

2.2 Energy Efficiency Requirements of the NCC ......................................................................... 14

2.3 ABCB Supporting Information ................................................................................................ 14

2.3 Jurisdictional Treatment of Class 1 and 10 Renovations ....................................................... 15

2.4 Jurisdictional Treatment of Alterations ................................................................................... 16

2.5 Jurisdictional Treatment of Additions ..................................................................................... 18

2.6 Jurisdictional Treatment of Existing Parts of Altered Dwellings .............................................. 19

2.7 Jurisdictional Treatment of Class 10 ...................................................................................... 20

3. Energy Efficiency compliance methods ...................................................................................... 21

3.1 NCC compliance methods ..................................................................................................... 21

3.1.1 Deemed to Satisfy - Elemental ........................................................................................ 22

3.1.2 Deemed to Satisfy - Energy Rating Method .................................................................... 23

3.1.3 Alternative solutions ........................................................................................................ 25

3.2 State and Territory compliance methods ............................................................................... 25

3.4 Victorian compliance method ................................................................................................. 27

3.5 Western Australian compliance method ................................................................................ 28

4. Discretionary powers of Building Certifiers ................................................................................. 30

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5. Educational material and advisory services ................................................................................ 31

6. Upgrades to Existing Buildings ............................................................................................... 33

7. Case studies .............................................................................................................................. 35

7.1 Methodology .......................................................................................................................... 35

7.1.1 Building plans ................................................................................................................. 35

7.1.2 Specification choices ...................................................................................................... 35

7.1.3 Material costing ............................................................................................................... 38

7.1.4 Energy costs ................................................................................................................... 38

7.1.5 Assessment costs ........................................................................................................... 39

7.1.6 Result selection............................................................................................................... 39

7.2 Results .................................................................................................................................. 40

7.2.1 Case Study Results, Energy Use .................................................................................... 40

8. Proposal for change and alternatives ...................................................................................... 44

9. Stakeholders ........................................................................................................................... 45

9.1 Building certifiers ............................................................................................................... 45

9.2 Accredited assessors ......................................................................................................... 45

9.3 Builders and Designers ...................................................................................................... 45

9.4 Homeowners ...................................................................................................................... 45

10. Proposed regulatory and jurisdictional change ...................................................................... 46

11. Good Regulatory Principles ...................................................................................................... 48

12. Action Plan................................................................................................................................ 49

13. Conclusions ............................................................................................................................. 49

10. REFERENCES ........................................................................................................................ 51

Appendix A: Case study building plans ........................................................................................... 52

Appendix B: Construction Costs ..................................................................................................... 54

Appendix C: Assessment results and costs for the case studies ..................................................... 57

Headings for tables ..................................................................................................................... 57

Case Study 1 ............................................................................................................................... 58

Case Study 2 ............................................................................................................................... 63

Appendix D: Online Surveys of Two Key Industry Groups: Certifiers & Energy Assessors .............. 68

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Executive Summary This report provides a pathway forward to improving the energy performance of Australian housing when buildings undergo renovations. Improvements to the energy performance of the existing building during building upgrade can be a cost efficient method to raise the energy performance of the Australian housing stock. Sustainability House surveyed stakeholders and confirmed that levels of confusion exist in the application of the National Construction Code (NCC) and state and territory regulations. The survey also confirmed that discretion applied by building certifiers undermines industry certainty and consistency. Two case studies, a large extension in relation to the existing building and a small extension, were used to demonstrate that improving the energy performance of the existing building at the time of renovation can provide a long term benefit for the householder. Background The National Energy Efficient Building Project (NEEBP) seeks to improve the design and construction of energy efficient buildings. NEEBP Phase One research identified significant industry confusion with the delivery of energy efficient alterations and additions. An opportunity was identified to overcome confusion by reviewing compliance solutions in each State and Territory, with the intention of identifying a best practice model. Objectives As part of NEEBP Phase Two projects, this project aims to investigate whether the current regulatory framework for the compliance of residential Class 1 and 10 alterations and additions is meeting the objectives of stakeholders including; the Australian Building Codes Board (ABCB), building certifiers, energy assessors, homeowners, builders and designers. Approach In order to identify ways to improve compliance and consistency in the application of the NCC energy performance requirements to alterations and additions, the study involved:

● A review of regulations and measures in each jurisdiction; ● Industry feedback through discussions with key stakeholders and online surveys of private

and council certifiers and energy efficiency assessors; ● Reviews of example compliance documentation in each jurisdiction; ● Case studies assessed using the Elemental DtS and NatHERS software compliance

pathways. Sustainability House’s RoboRater tool was used to run 1.8 million Nationwide House Energy Rating Scheme (NatHERS) comparisons for different building upgrade works.

● Two plans were assessed in each capital city over a range of specifications. ● Construction costs were calculated for each specification. ● Energy costs were estimated from the NatHERS software. ● Possible outcomes; DtS Elemental, NatHERS 6 star, the Victorian and WA

calculation methods and an improved DtS option where the existing building’s ceiling was insulated and weather seals were applied, were compared.

● Recommendations for changes to the NCC and state jurisdictional requirements.

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Findings This study found there is confusion and inconsistency in how the energy efficiency requirements are applied. Key issues identified include:

● NCC requirements apply to all new building works but do not apply to the existing building. ● As the NCC requirement does not apply to the existing part of alteration and addition

projects, each State and Territory has developed differing guidelines and/or regulations. In some jurisdictions retrofits to the existing building are required, in some they are encouraged, while in others no mandatory or voluntary improvements are required;

● Across all jurisdictions there is significant industry confusion on the definition of alteration and addition work, as well as the content and intention of requirements;

● In many jurisdictions certifiers have discretionary powers to determine on a case-by-case basis how energy performance requirements should apply, although they have limited understanding of what the energy performance requirements are, and the relative cost-benefits of their decisions;

● Some jurisdictions regulate assessment methods and compliance requirements based on the volume or area subject to alteration and addition works; and

● Energy assessors are making incorrect assumptions around the thermal performance of the existing part of the building. In some jurisdictions there are guidelines of how to assess the existing building.

The case study results indicate:

● The current methods of assessing alterations and additions have outcomes below the minimum acceptable construction standards set by the NCC; and

● Improving the thermal performance of the existing building has the potential to deliver a saving in energy costs which is greater than the construction cost. Additional insulation to the roof of the existing building was the most cost effective improvement.

As an example, the chart below shows the difference in total cost where the improvement costs are added to the heating and cooling electricity costs of one of the case studies over a 7 year period. The legend for the chart:

● DTS: The current standard practice, the existing building is left as is and the extension meets Elemental DTS

● 6 star: The least cost star rating greater than or equal to 6 stars. ● Vic: The least total cost star rating that achieved above the rating calculated using the

Victorian method. ● WA: The least total cost star rating that achieved above the rating calculated using the

Western Australian method. ● DTS Upgrade: The extension meets Elemental DTS and the existing part of the building

meets Elemental DTS for; Roofs (3.12.1.2), and Building Sealing (3.12.3). The chart indicates a saving in cost over the lifetime of the building for all methods compared with the addition only meeting the Elemental DTS.

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Total cost - Building + Energy cost v Climate

Recommendations The recommendation is to change the regulation to require altered and extended buildings to meet a cost effective standard of energy efficiency using methods which are: simple to apply, are similar to the methods used for new buildings, and provide both a clear Elemental DTS method and NatHERS (modelling) method. The logical place for a national change is in the NCC. Removing the state and territory jurisdictional requirements and replacing them with NCC regulations would also further the ABCB programs of Variation Management and Code Consolidation, however as the recommendation is to improve the thermal performance of the existing building, the recommendation may need to be taken up by the states and territories. It is proposed that:

● The Federal, State and Territory jurisdictions develop a definition of what constitutes alterations and additions work.

● An amendment is made to the Volume 2, Part 3.12 of the NCC, or to the state and territory

requirements, that sets a minimum performance standard for the existing part of an alteration or addition. Particularly:

● There is a requirement for the NCC Volume 2 Parts 3.12.1.2 Roofs, and 3.12.3 Building Sealing to apply to the existing parts of altered and extended buildings.

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● A calculation method, similar to the one developed in WA, to be developed and used to calculate an amended minimum NatHERS star rating for the altered or extended part of the building. The calculation method should incorporate the age of the existing building and the relative percentage of the alteration or addition to the existing building. The amended star rating will be lower than the 6 star assessment for new buildings.

In the case where the roof space is inaccessible the applicant can;

● Use another method of compliance, such as verification against a reference building, or

● Provide a cost benefit analysis to the building certifier as part of an application for a concession. As identified in NEEBP Phase One, concessions should be based on cost benefit rather than the building certifier’s discretion.

● Clear and simple compliance checklists for alterations and additions to be developed and

used for each stage of the compliance process.

● The state and territory jurisdictions alter their current requirements to refer to the NCC. Except in the cases of NSW and NT where similar changes are made to Building Sustainability Index (BASIX) and the NT Variation to Section 3.12.

● Energy performance requirements training to be developed and provided, particularly for

certifiers and energy assessors, but also for other relevant stakeholders such as builders, architects, property owners and developers

Stakeholder benefits Stakeholder benefits are identified for:

● ABCB - The introduction of these changes to the NCC will harmonise the treatment of alterations and additions nationally, a goal of the ABCB’s Variation Management and Code Consolidation projects.

● Builders and designers - Clearer and simpler regulation potentially reducing approval times for projects.

● Building certifiers - Clearer and simpler regulation reducing approval times for projects and reducing their potential liability.

● Energy assessors - Clearer and simpler regulation and reduction of potential errors through making incorrect assessments.

● Homeowners - Potential energy saving and other benefits from increased thermal performance.

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1. Introduction 1.1 Background The National Energy Efficient Building Project (NEEBP) broadly seeks to improve compliance with the building energy efficiency requirements in the National Construction Code (NCC). NEEBP is led by the South Australian government Department of State Development (DSD) on behalf of the Commonwealth and all State and Territory governments. Phase One of NEEBP sought extensive feedback through consultation with over 1000 industry stakeholders, regulators and policy makers across Australia to identify key systemic and process weaknesses, point of non-compliance and related issues. This initial project was delivered by Pitt&Sherry and Swinburne University of Technology, and incorporated a review of issues relating to new buildings, as well as alterations and additions. The Phase One report provided a detailed review of issues specific to alteration and addition building projects, incorporating residential and commercial building types. Their findings relating to alterations and additions included that:

● There appears to be substantial confusion in the building industry about how and when the NCC energy efficiency requirements apply to alterations and additions;

● Responsibility for the application of the regulation devolves from the NCC to local authorities through clauses around practicality;

● The opportunity presented for energy efficiency improvements in existing buildings at the time of alterations and additions is not being realised; and

● There is a lack of industry confidence in the older versions of the energy rating tools and difficulties are experienced by energy assessors in applying rating tools to the assessment of alterations and additions.

Phase One identified that an opportunity exists to overcome confusion around the assessment of alterations and additions by reviewing compliance solutions undertaken in each state and territory and identifying a best practice model which could be adopted. The NEEBP Phase One report provided several recommendations to improve clarity and consistency in the application of energy efficiency provisions for alteration and addition works:

● Triggers for the application of energy performance provisions to alteration and addition projects should be included in the NCC;

● The phrase ‘to the degree necessary’ is replaced with ‘to the degree cost-effective’ in the NCC;

● NCC energy performance requirements should apply to a ‘building or part thereof’; ● No area limitation to when the NCC requirements should apply to an alteration or addition

project; and ● New building works is either 1) excluded from complying, 2) required to comply, or 3)

required to comply, subject to a cost-effectiveness test.

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1.2 What Are Alterations & Additions? For the purpose of this review;

● ‘Addition’ projects are defined as new building works which extend the existing habitable floor area of an existing Class 1 and 10 buildings.

● ‘Alteration’ projects are changes to the external building fabric of an existing Class 1 and 10

that is subject to development approval. Between State and Territories, as well as at the local council level and individual certifiers, there is variation in what types of alteration works require development approval. This is discussed in further detail throughout this report.

1.3 The National Construction Code The NCC sets minimum performance standards for new buildings. One of the primary goals of the NCC is to “enable achievement of nationally consistent, minimum necessary standards of relevant safety, health, amenity and sustainability objectives efficiently”. The requirements are intended to provide net benefits, where the benefits to society are greater than the costs. The NCC is structured in levels.

● Level 1, the overall Objective. ● Level 2, Functional statements setting out the requirements to meet the objective. ● Level 3, Performance requirements “outline a suitable level of performance which must be

met by building materials, components, design factors, and construction methods in order for a building to meet the relevant Functional Statements and, in turn, the relevant Objectives.1”

The Performance Requirements of Part 2.6.1 state that “… a building must have, to the degree necessary, a level of thermal performance to facilitate the efficient use of energy for artificial heating and cooling…” In order to meet one of the core goals of the NCC, to provide a net benefit, energy efficiency requirements need to be balanced between costs and benefits. NCC energy efficiency provisions apply to all new building works, whether construction of a whole house, or alteration, addition or relocation of an existing house as required by a jurisdictional building authority. The provisions do not apply to unaltered existing dwellings unless required by a jurisdictional building authority, such as through a change of use. Variation Management and Code Consolidation The NCC receives its regulatory backing through being implemented by the state and territory jurisdictions. When enacting the NCC the states and territories can and do make changes. A nationally consistent code is an underlying principle of the ABCB Inter-governmental agreement2. Specific projects are:

● Variation Management, which aims to reduce state and territory variations, and

1 http://www.abcb.gov.au/about-the-national-construction-code/the-building-code-of-australia/hierarchy-of-the-performance-based-bca.aspx 2 http://www.abcb.gov.au/Initiatives/All/Variation-and-Harmonisation

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● Code Consolidation, an intergovernmental agreement to take reasonable steps to consolidate mandatory provisions into the NCC.

Both initiatives are stated to improve industry and national productivity. This report assumes the benefits of the initiatives can be taken as read. 1.4 Renovations of the Existing Housing Stock There is limited available data on the number and characteristics of dwellings that undergo renovations each year. The total value of work undertaken on renovations is estimated to account for about 12.5 percent of the total expenditure on residential building works (ABS 2015). HIA Economics forecast that the number of renovation projects as a proportion of new building projects will increase in the future. The data that does exist on renovations only applies to projects that are required to undergo building development approval, as only these need to comply with NCC requirements. Development approval requirements vary between State and Territories, as well as at the council level. Limited data also exists on the characteristics of existing housing stock and the nature of renovation projects in each State and Territory. Amongst the most comprehensive studies available was the study completed by the Victorian building regulator in metropolitan Melbourne (VBA 2013). Their findings identified that the average renovation project incorporated additions that increased the floor area by more than 60%, as well as alterations to 15% of the existing building at an average cost of $240,000. Renovation projects did not typically include sustainability features beyond NCC requirements. In terms of greenhouse gas emissions, residential energy use accounts for about 12% of the total energy use in Australia. Of this approximately 40% of energy is used for space conditioning in homes (EES 2008). As the majority of Australian housing stock constitutes existing buildings constructed prior to the introduction of energy efficiency requirements, there are significant opportunities to reduce greenhouse gas emissions by improving the building shell performance of the existing housing stock. 1.5 Potential benefits beyond energy efficiency The benefits of improving dwelling energy efficiency extend beyond reductions in energy use. Improved building sealing, for example, can not only improve energy efficiency but also occupant health and productivity by reducing the entry of dust, mould, toxins, moisture and pests into the home. One recent study finding, that 6.5 per cent of deaths in Australia are contributed to by exposure to cold weather, has been linked to the poor quality of Australian housing (Roberts 2015). The NEEBP Phase One report identified that many industry stakeholders believe there is a missed opportunity in the NCC to upgrade existing buildings at the time of performing renovations, as this provides the best opportunity to regulate improvements to existing structures with an energy efficiency focus. 1.6 Research approach - Identifying the problem This project aims to investigate whether the current regulatory framework for the compliance of residential Class 1 and 10 alterations and additions are meeting the objectives of the ABCB, including those set out in the NCC, and of other stakeholders. The research approach is to:

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● Review the current building approval process for alterations and additions to Class 1 and

attached Class 10 buildings in each jurisdiction, including identification of the circumstances when the energy efficiency requirements apply to alterations, additions and existing buildings.

● Obtain industry feedback from key stakeholders through conversations, online surveys and

the examination of compliance reports.

● Address the issues identified by NEEBP Phase One research.

● Compare and discuss the current jurisdictional outcomes using case studies. ● If needed, write recommendations for a pathway to improve the regulatory framework to

provide improved outcomes for stakeholders.

2. Review of Jurisdictional requirements and regulations 2.2 Energy Efficiency Requirements of the NCC The NCC 2015 Volume 2 sets out construction standards for Class 1 and 10 buildings. Part 2.6 provides energy efficiency performance provisions. The Performance Requirements of Part 2.6 are satisfied by complying Part 3.12, which provides separate compliance pathways for Elemental DtS and Software DtS, using the NatHERS software. New building work to Class 1 and 10 buildings, including alterations and additions, are required to demonstrate compliance as follows:

● Fabric, glazing & sealing - Class 1 and Class 10a buildings with a conditioned space ● Air movement - Class 1 ● Services - Class 1, Class 10a and Class 10b swimming pool associated with a Class 1 or

10a building. For the purpose of this review only treatment of Class 1 and enclosed, attached 10a buildings are required to demonstrate compliance with the energy performance requirements of the NCC. Requirements that apply to adding heating and/or pumping to an existing Class 10b swimming pool are not discussed in this report. 2.3 ABCB Supporting Information Chapter 12 of the ABCB Energy Efficiency Provisions for the BCA Volume Two Information Handbook 2015, provides national guidance on the treatment of alterations and additions to an existing Class 1 and 10 buildings. The ABCB Energy Efficiency Glazing Provisions for BCA Volume Two also provides some national guidance on the treatment of alteration and additions to existing Class 1 and 10 buildings. The guide advises that compliance requirements are at the discretion of the respective State and Territory Building Control Authorities, which may include consideration of existing building characteristics, as well as the type and extent of new building works.

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The ABCB glazing guidelines recognise that in some climate zones and depending on the orientation of new glazing in an alteration or addition, it may be very costly or impossible to achieve compliance. Consequently an alternate method is detailed which may be acceptable in some jurisdictions. The guideline advises assessment of the new and existing dwelling as if new glazing were applied uniformly throughout. 2.3 Jurisdictional Treatment of Class 1 and 10 Renovations Any provision of the NCC may be overridden or varied by State and Territory governments, and it is at their discretion how requirements are applied and enforced. Each jurisdiction provides additional information on the treatment of new building works to existing buildings. In some jurisdictions regulatory requirements apply while in others guidance notes have been developed to assist in the interpretation and application of NCC requirements. Table 1 summarises the documentation that is available and whether regulatory or non-regulatory measures exist in each State and Territory.

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Table 1. Regulatory and non-regulatory documents guiding the assessment of alterations and additions in each State and Territory.

Jurisdiction Regulatory or non-regulatory

Documents

Federal Non-regulatory ABCB Energy Efficiency Provisions for BCA 2010 – Volume Two Information Handbook ABCB Energy Efficiency Glazing Provisions for BCA 2010 – Volume Two Information Handbook

ACT Regulatory Building (General) Regulation 2008 SL2008-3 Republication No. 27 Building Act 2004 A2004-11, Republication No 32

NSW Regulatory ● BASIX Tool ● BASIX Guide: Using Simulation for Alterations and Additions Version 0.4, 2 October 2013

NT Non-regulatory Building Advisory Services Branch Building Note Edition Number 68

QLD Regulatory Queensland Development Code Mandatory Part 4.1 - Sustainable Buildings and supporting Guideline

SA Non-regulatory Building Advisory Notice 03/12

TAS Non-regulatory Building Regulation Advisory Note BRAN No.4 of 2013, issued 23-12-2013, revised and updated 14-1-2015

VIC Regulatory and Non-regulatory

● Building Regulations 2006 Regulation 608 ● Practice Note 2014-55 Issued July 2014

WA Non-regulatory WA Alterations & Additions Protocol for Energy Efficiency in Class 1 or attached Class 10 buildings

2.4 Jurisdictional Treatment of Alterations Many alterations don’t require development approval and so are not assessed for NCC compliance. Where compliance is required most jurisdictions provide some exemptions to energy efficiency regulation for alterations to existing buildings, these are detailed in Table 2. Typically alterations are exempt if they involve minor changes to the external building fabric, such as maintenance, repair, replacing cladding or changing a window. Jurisdictional guidance documents generally only discuss building fabric and glazing, without any reference to the other sections; building sealing, air movement and services.

http://www.legislation.act.gov.au/sl/2008-3/current/pdf/2008-3.pdf

http://www.legislation.act.gov.au/sl/2008-3/current/pdf/2008-3.pdf

http://www.legislation.act.gov.au/a/2004-11/current/pdf/2004-11.pdf

http://www.legislation.act.gov.au/a/2004-11/current/pdf/2004-11.pdf

http://www.basix.nsw.gov.au/basixcms/getting-started/using-the-basix-assessment-tool.html

http://www.basix.nsw.gov.au/basixcms/getting-started/using-the-basix-assessment-tool.html

http://www.basix.nsw.gov.au/basixcms/images/pdfs/BASIX-Guide-Using-simulation-for-alterations-and-additions.pdf




http://www.lands.nt.gov.au/__data/assets/pdf_file/0017/8171/BuildingNote68.pdf

http://www.lands.nt.gov.au/__data/assets/pdf_file/0017/8171/BuildingNote68.pdf

http://www.hpw.qld.gov.au/SiteCollectionDocuments/qdc-4-1-sustainable-buildings-guideline.pdf

http://www.hpw.qld.gov.au/SiteCollectionDocuments/qdc-4-1-sustainable-buildings-guideline.pdf

https://www.sa.gov.au/__data/assets/pdf_file/0005/6593/Building_advisory_notice_applying_energy_efficiency_measures_to_class_1_buildings.pdf

https://www.sa.gov.au/__data/assets/pdf_file/0005/6593/Building_advisory_notice_applying_energy_efficiency_measures_to_class_1_buildings.pdf

http://www.justice.tas.gov.au/__data/assets/pdf_file/0004/302971/BRAN_No_4_-_2013_revised_2015.pdf

http://www.justice.tas.gov.au/__data/assets/pdf_file/0004/302971/BRAN_No_4_-_2013_revised_2015.pdf

http://www5.austlii.edu.au/au/legis/vic/consol_reg/br2006200/s608.html

http://www5.austlii.edu.au/au/legis/vic/consol_reg/br2006200/s608.html

http://www.vba.vic.gov.au/__data/assets/pdf_file/0003/20397/PN-55-2014-Residential-Sustainability-Measures.pdf

http://www.vba.vic.gov.au/__data/assets/pdf_file/0003/20397/PN-55-2014-Residential-Sustainability-Measures.pdf

https://www.commerce.wa.gov.au/sites/default/files/atoms/files/ib042_alterations_and_additions_protocol_0.pdf

https://www.commerce.wa.gov.au/sites/default/files/atoms/files/ib042_alterations_and_additions_protocol_0.pdf

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Table 2. Treatment of alterations in each State and Territory.

Jurisdiction Treatment of Alterations

Federal All new building works must comply

ACT Alterations must comply with NCC provisions.

NSW Under the NSW Environmental Planning and Assessment (EP&A) Regulation 2000, developments that involve the alteration, enlargement or extension of a BASIX affected building (that is, a building that contains one or more dwellings, excluding hotel or motel), where the estimated construction cost of development is $50,000 or more, need to meet the BASIX requirements. Development for the purpose of swimming pool and/or spa with a combined size of 40,000L or more is also BASIX-affected (as Alterations and Additions). The trigger for BASIX requirements for Alterations and Additions is not directly related to type of work required (such as new framing members for walls or removal of linings).

NT NCC energy efficiency provisions should be applied to alterations where practical and appropriate. Examples of when it is not required include when replacing or changing a window or roof cladding.

QLD Alterations must comply with QDC 4.1 “as much as practical” where the proposed building work is subject to a building application.

SA If the alteration is to the external fabric then where reasonable DtS should apply. If the modifications are deemed minor, such as repairing or painting of a ceiling or roof, DtS requirements do not need to be met. A modification would need to meet DtS requirements where the roof cladding or ceiling linings are removed to the whole house. The energy efficiency with alterations should not be less than the energy efficiency without alterations.

TAS New works must comply with NCC provisions.

VIC Alterations must comply with Performance Requirements P2.6.1 (building) and P2.6.2 (services) of the BCA Volume Two if constructed prior to the 5 star standard introduction on 1 July 2004. For Class 1 buildings constructed to the 5 or 6 star standard post 1 July 2004 alterations must ensure that the energy efficiency standard of the existing building is maintained.

WA All new building works to Class 1 and 10 buildings to comply with NCC provisions.

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2.5 Jurisdictional Treatment of Additions The treatment of additions also varies between each jurisdiction, as detailed in Table 3. Compared to alterations, jurisdictions provide clearer recommendations that all new building works should comply with NCC requirements. However some states provide flexibility by using phrases like “as much as practical” or “at the discretion of building surveyors”.

Table 3. Treatment of additions in each State and Territory.

Jurisdiction Treatment of Additions

ACT Additions must comply with NCC requirements.

NSW Under the NSW Environmental Planning and Assessment (EP&A) Regulation 2000, developments that involve the alteration, enlargement or extension of a BASIX affected building (that is, a building that contains one or more dwellings, excluding hotel or motel), where the estimated construction cost of development is $50,000 or more, need to meet the BASIX requirements. Development for the purpose of swimming pool and/or spa with a combined size of 40,000L or more is also BASIX-affected (as Alterations and Additions). The trigger for BASIX requirements for Alterations and Additions is not directly related to type of work required (such as new framing members for walls or removal of linings).

NT Additions of partial or complete habitable rooms are required to comply with all measures for the new work. Only services are required to comply for non-habitable additions.

QLD Additions must comply with QDC 4.1 “as much as practical” where the proposed building work is subject to a building application.

SA Any added habitable rooms or extended portions thereof must comply with DtS provisions for the building fabric. Non-habitable rooms do not need to comply unless they are incorporated with additional habitable rooms. The energy efficiency of the addition should be not less than the energy efficiency of the building before the addition.

TAS New works must comply with NCC requirements.

VIC As detailed for alterations; and Extension works may only require partial compliance, at the discretion of building surveyors, if the extension is not greater than the lesser of either 25% of the floor area of the existing building or 1000m².

WA As detailed for alterations.

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2.6 Jurisdictional Treatment of Existing Parts of Altered Dwellings The treatment of existing Class 1, as detailed in Table 4, varies between jurisdictions, from jurisdictions with no retrofit requirements to jurisdictions requiring upgrades where the alteration and addition works represents more than 50% of the existing floor area. In many jurisdictions energy efficiency requirements apply when a structure is changing to a Class 1 or being relocated.

Table 4. Treatment of existing dwellings in each State and Territory.

Jurisdiction Treatment of Existing Dwellings

Federal The existing building is not required to comply unless it is subject to new building works.

ACT If substantial alterations are made to the existing building then the whole building must comply with NCC energy efficiency requirements. Substantial alterations are defined as more than 50% of the volume of the original building, including alterations made during the previous 3 years immediately before the day the application for building approval. The unaltered walls/ roof/ suspended floors of a substantially altered building need not comply if complying would require removal of more than 10% of walls/ roof/ suspended floors, or there is insufficient cavity space to accommodate insulation to achieve the R-value requirement. External glazing to the existing building is required to comply if it is not isolated from the addition. For example, where a living zone is extended onto a kitchen and forms part of the same zone, without doors to separate the zones, the existing kitchen glazing must comply with the Building Code Volume 2, Part 3.12.2.

NSW The EP&A Regulation does not have any reference to “Major alterations and/or additions”. “Major alterations and/or additions” can be understood as > 50% volume of the original building (as per ACT and VIC). However, the definition of BASIX-affected Alterations and additions based on construction value can apply even if the volume of work is < 50%. With a 4-bedroom house of say 250m2 for example, the addition of another room (say 10% of the original volume) can trigger BASIX requirements when the cost of construction >= $50k.

NT No modifications are required for the existing part of a dwelling unless changing from a Class 10 to a Class 1, in which case compliance is required with all energy efficiency provisions.

QLD Where the proposed building work represents more than 50 percent of the existing dwelling’s volume, the building certifier has discretion to apply current building assessment provisions. This discretion can be used when

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applying relevant energy efficiency requirements under QDC 4.1 for an alteration, addition or relocation.

SA Depending on modifications and compliance method used upgrades to the existing building may be advised.

TAS Existing buildings are not required to be upgraded at the time of alteration and addition works.

VIC Upgrades are not required to the existing building unless the volume of the any new works completed within the previous 3 years represents more than 50 per cent of the volume of the original building, then both the existing and alterations work should comply with the requirements. Where there is access to the roof space ceiling insulation should be installed to the existing building. Similarly, where sealing to the existing building is practical and achievable it should be undertaken.

WA All new building works to comply with NCC requirements. The existing building is required to comply with the NCC if changing building classification (e.g. Class 10 to Class 1).

2.7 Jurisdictional Treatment of Class 10 Table 5. Treatment of enclosed and attached Class 10 buildings in each State and Territory.

Jurisdiction Treatment of Class 10 Building

ACT Class 10 buildings are required to comply with NCC provisions

NSW Class 10 buildings are required to comply with NCC provisions

NT Class 10 building with a conditioned space should comply with new building works requirements as detailed for alterations and additions.

QLD Enclosed and attached garage to a Class 1 building is required to meet QDC 4.1.

SA The addition of an attached Class 10 building requires insulation to the ceiling/ roof if the roof area is not separated from the existing building. Conservatories/ sunrooms are not required to comply with energy efficiency provisions provided the thermal performance of the existing building is not compromised.

TAS Requirements for new building works apply to non-habitable outbuilding with a conditioned space.

VIC Class 10a buildings with a conditioned space should comply with NCC provisions.

WA All new building works to Class 10 buildings to comply with NCC provisions.

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3. Energy Efficiency compliance methods Documentation demonstrating compliance with the energy efficiency requirements is completed before construction commences. The building authority, the council or private certifier, determines whether the information presented is accepted as demonstrating compliance with the NCC or jurisdictional requirements. Completing the energy efficiency requirements is done by a number of industry professionals or their staff, including; accredited and non-accreted energy assessors, builders, building designers, architects, homeowners, building product manufactures and building surveyors. To date the majority of energy efficiency assessments have been done from information supplied in the form of written documentation. Generally the people creating the documentation do not visit the site. The Certificate IV in NatHERS assessment is in the process of becoming a requirement for accredited energy assessors using the NatHERS software to issue star rating assessments. The Cert IV includes sections on site visits and methods of drawing up existing building in preparation for entry into the NatHERS software. In the discussion of compliance methods below it is assumed that the provider of the documentation and building authority can correctly identify the requirements. Additionally it is assumed that the correct information is provided. 3.1 NCC compliance methods The NCC applies to all new building work unless a dispensation has been given by the building authority. Changes to the existing building are determined by its jurisdiction. Assessment tools, principally the NCC glazing calculator and the NatHERS software, require a whole building or whole floor to be assessed, blurring the division between new and existing work. There are a number of ways a building, new or altered, can show compliance with the NCC Vol 2 Performance requirement P2.6. The available methods include:

● Deemed to Satisfy - Elemental ● Deemed to Satisfy - Energy Rating (software): ● Alternative Solutions:

o Verification using a reference building (V2.6.2.2) o Other Verification Methods o Expert Judgement

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3.1.1 Deemed to Satisfy - Elemental Compliance is demonstrated by meeting the minimum insulation levels and external glazing compliance is demonstrated by meeting the glazing calculator. Requirements also apply to building sealing, air movement and services. This method is inflexible as each aspect, the roof, walls, floors and glazing needs to meet a minimum performance requirement. There is no option to trade performance above the minimum in one aspect of the building with another aspect which is lower than the minimum. The most recent increase in stringency was introduced in BCA 2010. Buildings constructed before this can have trouble meeting the minimum performance levels in a cost effective manner. Generally the building industry has decided it is not cost effective to increase the performance of:

● Walls, where adding insulation is not possible, as in cavity masonry construction, or the perceived cost of the removal and replacement of cladding or internal linings.

● Ceiling and roofs, where adding insulation is not possible due to lack of space. ● Glazing where the removal and replacement is required.

Glazing After roof insulation, glazing is the most influential single aspect influencing building thermal performance. The NCC sets minimum levels for glazing insulation and solar heat gain for glazing using a complex calculation formula. A glazing calculator spreadsheet is supplied to simplify the process.

The glazing calculator is intended to be applied to a “whole storey” of a house. The ABCB guidance notes (ABCB 2015) advise that the glazing of the existing dwelling is assessed “as if the new glazing were uniformly applied to the whole storey, but to require complying glazing to be installed only in the alteration or addition”.

This approach allows a complying glazing specification to be applied for the whole storey of the dwelling in the compliance documentation, but only installed to the addition. The cost of removing and replacing existing glazing is generally considered to be unfeasible. However the final building thermal performance will be below the minimum standard set by the NCC.

In addition, where no north facing glazing is included in the calculation it may be difficult to achieve compliance as heavy favourable weighting is given to the presence of northern glazing. In these cases the building either needs to get a concession from the building authority or use another method to show compliance. Air-leakage and services Other aspects of building energy efficiency beyond the structure are required for new buildings to comply with the DTS requirements. These include:

● Building sealing: stopping unwanted air-leakage from doors, windows, exhaust fans and other penetrations.

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● Air movement: ensuring sufficient ventilation is available. This is also covered in NCC Vol2, Section 3.8.5 Ventilation.

● Services: including lighting, insulation of ductwork and hot-water heating. 3.1.2 Deemed to Satisfy - Energy Rating Method The Nationwide House Energy Rating Scheme (NatHERS) uses predictive modelling software to meet or exceed whole-of-house annual energy usage targets. The software takes building design and specification inputs, and calculates a star rating using a climate file, estimated comfortable temperature ranges, usage patterns and starbands. The star rating is from 0 to 10 stars with a 10 star building expected to be comfortable all year with no external heating or cooling. For dwellings that comply using this method, the whole house, including new building works and the existing structure, must be assessed using accredited NatHERS star rating software. Software assessment is more flexible than the Elemental DTS method, as the software assesses the whole building rather than the constituent parts The NCC sets a minimum star rating requirement of 6 Stars in most jurisdictions. In some climate zones and jurisdictions, such as Climate Zones 1 and 2 under the NCC, and in QLD, optional credits can be used towards meeting the energy equivalence requirement (via a compliant outdoor living area and/or a photovoltaic (solar) energy system). The state and territory jurisdictions encourage the building surveyors to only accept NatHERS certificates from accredited energy assessors. Accredited assessors are professionals who are accredited by an Accrediting Assessor Organisation. Training for accredited assessors is in the process of being changed to require a Certificate IV in NatHERS assessment (Cert IV). The Cert IV includes a requirement for skills in investigating and drawing existing buildings. Energy ratings on alterations and additions are problematic. Issues can include:

● Assessments from un-trained or non-accredited assessors ● Existing building can perform poorly, reducing the overall efficiency, particularly if

constructed before energy efficiency requirements were part of the NCC. ● Costs involved with upgrading existing buildings. ● Incorrect assumptions of construction and materials of existing buildings. This can include

factors such as missing, old or removed insulation, shading from adjacent buildings and incorrect assumption of air-leakage. For accredited assessors these assumptions should be reduced where an accredited assessment is requested after the introduction of the Cert IV.

● Where older buildings are being altered or extended one common requirement of homeowners is increased glazing for light and ventilation. This can lead to large glazing areas in relation to the floor area of for the alteration or addition leading to poor thermal performance and low star rating.

It is possible to correct each of these issues, but they can meet resistance by differing from client intentions or are deemed to be too expensive.

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A NatHERS software assessment is done on a whole building. Where the building does not meet the mandatory minimum changes need to be made to the design or specification to increase the buildings thermal performance to meet the minimum. With an altered or extended building the design of the existing part of the building is fixed and the specification exists. Changes to improve the specification of the extension may not improve the thermal performance of the whole building sufficiently to meet the mandatory minimum. There has been industry acceptance that it is not reasonable to ask the homeowner to renovate the existing building to meet the thermal performance requirement. Such renovations could involve removing and replacing existing windows or adding insulation to solid walls. There have been two methods put forward to address this issue;

● In SA and TAS it is possible to conduct the NatHERS assessment with materials which have improved thermal performance to the whole building, but only require the improved thermal performance materials to be used in the extension or alteration leaving the existing building as is. The issue with this method is that the house receives a 6 star assessment for a building which performs below the 6 star level. This could be a serious issue in the future if disclosure of the energy performance of the building becomes a national requirement. In that case the owner of the upgraded building would assume their building is at 6 star whereas the actual performance may be much lower.

● In Vic and WA where methods have been devised to give the altered building an adjusted star rating for the completed building. Both methods use the age of the existing building and the relative size of the alteration in the calculation.

3.1.2.1 NatHERS Modelling Protocols In addition to the training accredited assessors receive, the NatHERS administrator publishes Technical Notes which provide some guidance on how to model alteration and addition projects. The information advises that:

● Accredited NatHERS software assessors should use the software in regulatory mode for assessing buildings.

● NatHERS software tools must assess a whole building, not a part of a building, and ● State and territory jurisdictions have alternative modelling methods

3.1.2.2 NatHERS Modelling Assumptions The absence of complete or reliable information has presented a major issue for assessors attempting to model the existing building. Based on a review of example compliance reports from each jurisdiction and discussions with assessors across the country, a range of assumptions are currently made about the existing building specifications when using NatHERS modelling software. In some jurisdictions, assessors do not make any assumption, as they are advised to model the whole building as if glazing and insulation requirements were applied uniformly throughout irrespective of the existing building specifications. In other jurisdictions, such as NSW, no advice is provided but assessor's record their

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assumptions and submit them with the compliance report. A review of example compliance reports identified inconsistency between information reported and assessment approaches. The introduction of the Certificate IV in NatHERS assessment requires assessors to be able to investigate and assess additions and alterations has addressed this issue through there will also need to be a change in how energy ratings are conducted for assessors to visit site. 3.1.3 Alternative solutions

3.1.3.1 Verification against a reference building An NCC prescribed method, V2.6.2.2 is intended to apply to whole Class 1 buildings and to an enclosed Class 10a building attached to a Class 1 building. Predictive modelling software is used to compare the proposed building with a reference building. The reference building is modelled as designed except using the DtS Elemental Provisions of Part 3.12 in accordance with 3.12(a)(ii). This is one of the most poorly understood of the assessment methods. Survey feedback indicated that more than 80% of assessors never use this compliance method for the assessment of alterations and additions, although it provides more achievable energy performance standards than the Energy Rating method and is not restrictive for certain designs or construction types like the Elemental method. V2.6.2.2 provides a flexible modelling approach which can be readily applied to the assessment of alteration and addition projects. Using software to model the reference and proposed building can lead to the same issues with assumptions and incorrect data outline in section 3.1.2.2 above.

3.1.3.2 Other verification methods In theory, any building construction or specification that can meet the NCC performance requirement and can be documented to show compliance is acceptable. In practice the building certifiers can be reluctant to take responsibility for new, innovative methods especially if there is no clear chain of responsibility. The NCC is moving towards a performance based code and new verification methods may be introduced in the future

3.1.3.3 Expert Judgement Judgement by an expert who has the qualifications and experience to determine whether a Building Solution complies with the Performance Requirements. Survey feedback from certifiers in WA, QLD, SA, NSW and Vic indicated that expert judgement is used at least some of the time in these jurisdictions. No example reports were obtained to demonstrate the application of this compliance method to an alteration and addition project. 3.2 State and Territory compliance methods In most jurisdictions all of the NCC compliance methods can be used, although the guidance documentation often creates confusion around this by referencing some and not others. A summary of recommended energy performance compliance methods by State and Territory Regulators is provided in Table 6.

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To address the issues of applying the NCC Energy Rating method to alteration and addition projects, several jurisdictions provided guidance documentation:

● SA and TAS recommend that the whole building is assessed as if glazing and insulation requirements were applied uniformly throughout, but the building constructed with performance measures to the addition only. Consequently while the building has been rated to 6 stars for compliance, it does not actually achieve this performance standard. This may cause issues for the current or future owners who may expect that the building performs at a 6 star level.

● QLD regulators recommend that when using NatHERS software to assess energy efficiency, the proposed alterations and additions are modelled including the kitchen area as a reference point (Queensland Development Code, 5.3.4 Alterations to an existing house or townhouse).

In QLD and NT when applying the expert judgement method expert consultants are nominated- from the Queensland Peer Review Panel. The appointed expert appraises available information about the proposed alterations and additions and determines whether or not a building complies. The NSW Building Sustainability Index (BASIX) energy efficiency compliance methods for alterations and additions are similar to NCC requirements. In the majority of cases compliance is achieved using the DIY method which is designed to be approximately equivalent to DtS Elemental using BCA 2009 insulation and glazing requirements for new building works. In some instances BASIX administrators can approve the use of the Simulation Method which is equivalent to the NCC Verification using a Reference Building (V2.6.2.2) approach. Projects can apply to use the Simulation method where there are practical or legal constraints preventing full compliance with the BASIX requirements, including heritage considerations, structural limitations, or strata restrictions in unit buildings. The NCC methods allows alternative solutions to be developed as a compliance verification method. Two states have opted to develop alternate solutions under the verification methods: VIC and WA. These approaches are reviewed in further details below in Sections 3.4 and 3.5.

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Table 6. Energy performance compliance approach by State and Territory Regulators.

Jurisdiction Elemental Energy Rating

V2.6.2.2 Expert Judgement/ Other Alternative Solution

State-Specific Verification Method

ACT Yes Yes Yes Yes -

NSW Yes - BASIX DIY

- Yes - BASIX Simulation

- -

NT Yes Yes Yes Yes -

QLD Yes Yes Yes Yes -

SA Yes Yes Yes Yes -

TAS Yes Yes Yes Yes -

VIC Yes Yes Yes Yes Yes

WA Yes Yes Yes Yes Yes

3.4 Victorian compliance method Alterations and additions to Class 1 and 10a buildings with conditioned spaces constructed prior to 1 July 2004 can be assessed using one of several different compliance methods. These include DtS Elemental and Energy Rating, as well as Alternative Solutions, including v2.6.2.2. Buildings constructed to the 5 or 6 star standard post 1 July 2004 must ensure the energy efficiency of the existing building is maintained. When using the Elemental method to achieve compliance, building additions are required to comply with the NCC fabric provisions for the extended portion, although partial compliance may be permitted by the building certifier if the addition is only small (25% of floor area or 1000m², whichever is less). For alteration works that include replacement of existing elements, such as roof or wall cladding or wall lining then the new works should also comply with the BCA fabric provisions. When assessing compliance of the extension glazing using the glazing calculator, a recommended approach is to apply the glazing type for the extension uniformly to the whole storey, but only require the complying glazing to the extension. This principle can be applied when using either of the DtS methods: Elemental and Energy Rating. Where the Energy Rating method is used to assess a building the whole building must be rated, but only the new building works are subject to requirements unless the extension represents 50% or more of the existing floor area, in which case the whole building should comply.

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The Victorian Method Where the building was constructed before 2004 and the floor area is less than 50% of the total area, two assessments are required: one to establish a star rating for the existing building and another to demonstrate that the alteration meets the minimum required overall star rating calculated using an approach unique to Victoria. The calculation method is detailed below and uses the proportional volumes of the existing building and extension to determine the overall star rating requirement. For an addition(s)/extension(s) that impact less than 50% of the floor area in the past 3 years, the formula is: (Ve x SRe) + (Vn x SRn) = SRr (Ve + Vn) Where: Ve = Existing internal dwelling volume, Vn = New work internal volume remaining after work completed, SRe = Existing house star rating, SRn = New house star rating, SRr = Required overall star rating. For example, if Ve = 203.7 m³ Vn = 20.8m³ SRe = 3.2 stars SRn = 6.0 stars. The required overall star rating (excluding any volume of new internal work (Vni)): SRr = (203.7 x 3.2) + (20.8 x 6.0) (203.7 + 20.8) = 3.5 star requirement. For alterations to an existing dwelling including internal works, the formula becomes: [(Ve – Vni) x SRe] + [(Vn + Vni) x SRn] = SRr (Ve + Vn) Calculation including internal works in existing building: Ve = 203.7 m³ Vn = 20.8m³ Vni= 35.6m³ SRe = 3.2 stars SRn = 6.0 stars The required overall star rating (incl. the Vni): SRr = ((203.7 - 35.6)x 3.2) + ((20.8 + 35.6)x 6.0) (203.7 + 20.8) = 3.9 star requirement. The adjusted minimum performance requirement should give an indication of the thermal performance of the altered building. While the adjusted star rating is lower than the 6 star minimum performance requirement set by the NCC, it doesn’t raise expectations of performance for the homeowner or subsequent purchaser as is the case is the case with the SA & TAS method. 3.5 Western Australian compliance method Alterations and addition projects in WA can choose to comply under alternate methods set out in the Protocol, or another alternative solution or the DtS provisions. The three methods described in the Protocol are: 1. Elemental Provisions option - applies targets to provide reasonable allowances for the likely performance of the existing building; and 2. NatHERS option - an alternate star rating method using NatHERS software that reduces the total star rating requirement from 6 stars. This approach allows the whole-of-house star rating method to be applied when it may not be cost-effective or feasible to improve the existing building to achieve 6 stars.

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3. Services option – applies targets to BCA Part 3.12.5 that make reasonable allowances for the likely performance of existing services. The NatHERS option of the Protocol sets out an alternative calculation method that makes reasonable allowances for the likely performance of the existing building when undertaking alterations and/or additions of Class 1 and 10 buildings. In an approach similar to the Victorian method, for the NatHERS option an area weighted adjustment factor is used to calculate a proportional star rating which considers the total areas of the existing building and new works. The area weighting adjustment star rating for the existing building varies according to building age: ● Existing area approved before 1 May 2004 - 2 stars; ● Existing area approved before 1 May 2006 - 3 stars; ● Existing area approved before 1 May 2012 - 4 stars. The area weighted adjustment factor only applies to dwellings when the alteration or addition is greater than 10% and no more than 80% of the dwelling. When the affected proportion exceeds 80% the whole building is required to achieve a star rating no greater than that equivalent to requirements of BCA 3.12.0.1. When the affected proportion is less than 10% the target star rating for the whole building is reduced to 2, 3 or 4 stars depending on the existing area was approved, in accordance with dates outlined above. By applying a minimum performance requirement to the existing building, the WA approach encourages energy performance improvements to the existing building. This is also a simplified approach when compared with the Vic method as the required star rating can be calculated easily, without relying on the initial star rating to determine the required rating.

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4. Discretionary powers of Building Certifiers In all State and Territories it is the responsibility of building certifiers to provide building approval, inspections and certification. In some states certifiers are also permitted to produce energy efficiency compliance reports and other compliance documentation, in addition to the approval. In some jurisdictions certifiers are employed by councils, in some jurisdictions certifiers are privately employed, while in others regulators permit both private and council certifiers to operate. Most jurisdictions permit some level of discretionary powers for certifiers to determine the appropriate level of compliance for the new works and/or existing structures, as summarised below in Table 7. In some jurisdictions, certifiers are recommended to exercise their professional judgement and consider factors such as cost-benefit, technical impracticability and difficulty in applying their discretion. Certifiers are recommended to prioritise health and safety, while given greater flexibility to interpret and apply sustainability requirements so as to not provide an unreasonable requirement where the benefit is outweighed by the cost.

Table 7. A summary of the degree of discretionary powers of certifiers in each State and Territory

Jurisdiction Discretionary Power of Certifiers

ACT None

NSW Limited discretionary powers

NT Flexibility to interpret and apply NCC requirements for new works

QLD Is determined on a case-by-case basis, particularly the extent to which the existing structure needs to comply with QDC 4.1.

SA “Appropriate level of compliance” determined by certifier in accordance with SA guidelines

TAS Unclear from guidance documents

VIC Regulation 608 provides certifiers with powers to permit partial compliance, which can be applied to both the new and existing structures

WA Limited discretionary powers

Survey feedback from certifiers indicated that they exercise these powers in a number of circumstances including: ● heritage buildings where requirements cannot be implemented; ● for minor alterations such as internal changes to one window; ● when the requirement seems unreasonable; and ● where jurisdictional regulations and guidelines allow them to, which may extend to all aspects of the new building works and existing structure.

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The benefits of this approach are suggested to include flexibility for applicants to achieve realistic energy efficiency performance outcomes which consider individual variations in existing dwellings and renovations projects, as well as conflicting requirement such as heritage listing. Nearly three-quarters of certifiers reported that they consider design and construction limitations in older dwellings when considering energy efficiency compliance requirements for alterations and additions. Industry concerns have also been raised throughout Australia in allowing flexibility in the application of regulatory requirements. The Phase One NEEBP report suggested that “discretion creates uncertainty, and potentially scope for pressure to be brought to bear upon parties to exercise discretion in a particular direction”. In many jurisdictions building applicants can nominate a private certifier who may risk future work opportunities if applicants perceive that the certifier is not lenient enough. Ten per cent of survey respondents, spanning VIC, ACT, QLD and NT, reported that they consider relationship maintenance when applying discretionary powers to determine energy efficiency compliance requirements for alteration and addition projects. Flexibility for certifiers to determine compliance requirements on a case-by-case basis also raises questions about how closely outcomes align with NCC performance requirements and optimise cost-benefit outcomes. Industry feedback indicates that most certifiers have received limited training, if any, in the relative energy performance impact of building design features and their costs to understand the ramifications of their decisions. Survey feedback indicated that certifiers often seek advice from energy efficiency assessors about regulatory requirements; however industry feedback indicates that seldom do certifiers seek advice on relative performance benefits when applying their discretionary powers. In addition to discretionary powers of certifiers, in Victoria the Building Appeals Board (BAB), an independent statutory body established under the Building Act, has the power to waive, modify or vary the provisions of the Regulations and the NCC on a case-by-case basis, including those relating to energy efficiency. If the certifier does not grant application for partial compliance, review by BAB can be requested by the applicant. 5. Educational material and advisory services Survey feedback from energy assessors and certifiers - the two stakeholder groups with the greatest responsibilities to understand and apply energy efficiency requirements to Class 1 and 10 buildings, indicated that there is significant confusion about requirements and measures. Half of certifier e-survey respondents reported that they find energy efficiency requirements and measures complex and difficult to understand. This perception was also shared by more than half of energy assessors, despite their high level of experience as assessors with more than 80% of e-survey respondents having worked in their profession for five or more years. Certifiers reported that they most commonly seek clarification on energy efficiency compliance requirements for alterations and additions from the following sources;

- NCC (86%), - Jurisdictional regulations and measures (58%), - Energy efficiency consultants (58%), - ABCB guide notes (30%), - Work colleagues (30%),

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- Internet (20%), and - NatHERS Technical Notes (20%).

Energy assessors reported that they seek clarification from;

- NatHERS Technical Notes (76%), - NCC (75%), - Jurisdictional regulations and measures (63%), - ABCB guide notes (46%), - Internet (30%), - Work colleagues (19%), and - Local council (17%).

It is interesting to note that while more than half of energy assessors reported that they find regulations and measures complex and confusing, certifiers regularly seek clarification on requirements from them. This highlights the need for improved clarification and education material to guide on energy efficiency regulations and measures for renovations. Energy assessors are trained in the use of NatHERS software, but in the past have not received the same level of training in the NCC or state or territory requirements. In some jurisdictions advisory services are available to certifiers, applicants and the broader construction industry. In SA certifiers can seek an expert opinion from the Building Rules Assessment Commission about the application of regulations for a fee of $461. In NSW a free BASIX helpdesk service is made available via phone, email and post to advise on the appropriate application of the Simulation method and answer other queries. The response from the surveys can be seen in Appendix D.

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6. Upgrades to Existing Buildings Although existing building upgrades are not required in most jurisdictions when undergoing alterations and additions, some jurisdictions suggest voluntary changes are adopted. In Victoria guidelines encourage ceiling insulation and building sealing improvements where practical and achievable. In Tasmania ceiling and floor insulation upgrades are advised where accessible, particularly adjacent to new building works. Addition projects often increase the volume of buildings that are subject to space conditioning and therefore the amount of energy required for heating and cooling. Unless retrofit improvements are made to increase energy efficiency of the existing building shell, then it is likely that the outcome will be increased building energy use irrespective of energy performance requirements for the new building works. This is one reason to consider adopting retrofit requirements for the existing building in future NCC or jurisdictional requirements. There are a range of retrofit options that could feasibly be applied to the existing building to improve energy efficiency and reduce greenhouse gas emissions, including:

● Measures to improve building shell performance, such as insulation (roof space and where feasible, external walls), shading and improving air tightness;

● Upgrading services by replacing inefficient lighting, space conditioners, hot water systems; and

● Installation of solar PV or other improved energy supply options. Survey feedback from assessors and certifiers as to what upgrades to the existing building they considered to be reasonable to require as part of the building approval for Class 1 dwellings varied significantly between assessors and certifiers. While assessors provided strong support for a range of retrofits, certifiers indicated limited support for potential retrofit requirements to the existing dwelling. Assessors provided strongest support for existing building retrofits which add ceiling insulation and improve building sealing and air tightness, including sealing wall vents and other cracks and gaps, self-sealing exhaust fans and sealing around windows and doors. Of the proposed upgrade options, certifiers provided the strongest support for adding ceiling insulation, with more than 90% indicating that they believed it should be added in at least some instances. A common reason cited by building certifiers to avoid energy efficiency requirements for the existing building was costs and difficulties in applying retrofits to the existing building. There is also a danger in adopting more stringent regulations for alterations and additions which discourage renovations or applicants to demolish and rebuild rather than retain the existing structure and materials. One certifier highlighted that reuse of existing building materials should be encouraged and “at no stage should legislation require the removal and replacement of existing building materials in order to achieve energy efficiency measures”. Replacing existing materials can detrimentally increase

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greenhouse gas emissions produced in the manufacture and transportation of new building materials. However as the current energy efficiency regulations do not consider embodied energy, this should also be considered in determining cost-benefit outcomes of regulations. Industry stakeholders identified a range of scenarios where ceiling insulation retrofits to the existing building can be onerous, particularly raked ceilings with no roof space access. However improvements to building sealing, and retrofitting of ceiling or roof insulation where the roof space is accessible, represent relatively cost-effective compliance solutions to achieve significant improvements in energy performance. A 2011 report The Value of Ceiling Insulation: Impacts of Retrofitting Ceiling Insulation to Residential Dwellings in Australia found that the payback period was five or less years across most jurisdictions, although contemporary payback periods are likely to be shorter due to energy price increases since this report was published.

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7. Case studies To better understand what impact these methods have on energy performance outcomes, two case studies were reviewed in each capital city to compare outcomes under several compliance methods and potential approaches. 7.1 Methodology 7.1.1 Building plans The plans were chosen as representative examples of typical building designs and standard practice in extensions. The size of the extension in relation to the existing building can impact the comparative change in energy use between the extended and existing buildings. There is a change in the requirements in some jurisdictions with respect to the size of the extension in relation to the existing building.

● Case study 1 is a large extension in relation to the existing building. ● Case study 2 is a small extension in relation to the existing building.

The case studies were assessed in the FirstRate5 software. Floor plans can be seen in Appendix A. 7.1.2 Specification choices The existing and extended building for both scenarios was assessed using FirstRate5 software. The climates used to assess the case studies are listed in Table 8.

Table 8: NatHERS Climate Files and postcodes

Proposed Climate Files

Location, Postcode NatHERS CZ

Darwin, 800 Climate – 01

Brisbane, 4000 Climate – 10

Perth, 6000 Climate – 13

Adelaide, 5000 Climate – 16

Richmond(NSW), 2753 Climate – 28

Tullamarine, 3043 Climate – 60

Canberra, 2600 Climate – 24

Hobart, 7000 Climate – 26

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Both buildings were specified as brick veneer, with a metal clad pitched roof and a concrete slab on ground floor. It was assumed that:

● the extended part of the building was sealed as required by the NCC; and ● the roof space of the existing building was accessible for the installation of insulation.

A range of building specification options was run using RoboRater. Independently developed by Sustainability House, RoboRater is an innovative software tool which automates building thermal simulation to test the effect of design changes. RoboRater is compatible with files from NatHERS approved software (AccuRate, FirstRate5 and BERS Pro). It rapidly assesses how a dwelling will perform with a range of construction and specification types. More than 1.8 million results were assessed. The range of specification choices can be seen in tables 9 - 16.

Table 9 - Existing ceiling insulation options - Pitched steel roof

Option 1 Option 2 Option 3 Option 4 Option 5

Building: Existing

Insulation None R2.5 R4 R5 R6 Roof colour Light Medium Dark (Reflective foil under the roof was not modelled)

Table 10 - Existing sealing options & ceiling fans

Option 1 Option 2

Building: Existing

Draft & window seals Unsealed sealed Ceiling fans None Living areas and bedrooms

Table 11 - Existing Glazing

Option 1 Option 2 Option 3 Option 4 Option 5

Building: Existing

Reference alstd low e al tint al dg low e al cp

Frame Aluminium Aluminium Aluminium Aluminium Aluminium

Glass Single clear Low emission Single tinted Double clear/low E Comfort plus

U-Value 6.5 4.37 6.2 3.8 4.5

SHGC 0.75 0.63 0.55 0.55 0.45

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Table 12 - Extension wall options - Brick veneer

Option 1 Option 2

Building: Existing

Insulation R2 R2.5

Table 13 - Extension ceiling insulation options - Pitched steel roof

Option 1 Option 2 Option 3 Option 4

Building: Existing

Insulation R2.5 R4 R5 R6 Roof colour Light Medium Dark

Table 14 - Extension Glazing

Option 1 Option 2 Option 3 Option 4 Option 5 Option 6

Building: Extension

Reference alstd low e al tint al dg low e al cp tim dg low e

Frame Aluminium Aluminium Aluminium Aluminium Aluminium Timber

Glass Single clear Low emission Single tinted Double clear/low E Comfort plus Double tint/low E

U-Value 6.5 4.37 6.2 3.8 4.5 1.79

SHGC 0.75 0.63 0.55 0.55 0.45 0.45

Table15 - Extension ceiling fans

Option 1 Option 2

Building: Extension Ceiling fans None Living areas and bedrooms

Table 16 - Extension floors - Concrete slab on ground

Option 1 Option 2

Building: Extension Floor insulation None R1 underfloor insulation

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7.1.3 Material costing Construction costs were sourced from various organisations including: Rawlinsons, Plus Spec, Kingspan, Fletchers Insulation, Fairhaven Homes, Hotondo Homes, No Gap Insulation, Technoform, Bradnams. Painted plasterboard linings and single clear glazed aluminium framed windows have been assumed to have been installed as part of standard construction. Costs are expressed as the cost of: adding insulation, improving windows, adding ceiling fans or applying seals to the building. While efforts were made to determine reasonable costs, feedback from previous studies has shown there is a large amount of price difference in the market. It is suggested that the costs given show the relative difference in costs of materials rather than an exact estimate. It was assumed that the existing buildings were constructed before 2004. Construction costs are listed in Appendix B.

Removal, improvement and restoration costs for the existing building There is an assumption that the cost of removing internal linings to install insulation and replacing windows would impose a prohibitive cost on the project. This is the reason that building certifiers are given discretion to allow partial compliance. In an attempt to test this assumption in the case studies it has been assumed:

● Flat ceilings with pitched roofs in the existing building allow access to install insulation. ● There will be trades on site capable of:

○ Removing, replacing and making good windows. ○ Removing, and replacing painted plasterboard to the external walls.

The additional cost estimate of the removal and replacement for: ● Plasterboard to the external walls is $49.5 /m2. ● Windows is $120 /m2.

7.1.4 Energy costs NatHERS star ratings are indications of the potential for a building to be used in an energy efficient manner. NatHERS software predicts heating and cooling loads based on a set of comfortable temperature bands and an occupancy pattern. While it is unlikely that a real household would use exactly the same energy for heating and cooling as predicted, energy costs have been calculated and are subject to the following assumptions:

● Assumptions used in the NatHERS software. These include: Typical Meteorological Year (TMY), number of occupants and times of occupation, comfortable temperature ranges, air leakage, operability of window openings and shading.

● Accuracy of assessment of existing buildings, particularly the assumptions made regarding the existing building as indicated by the surveys conducted for this report.

● NatHERS software does assume a Coefficient of Performance (COP) of the heating and cooling plant. An all electric split air-conditioning system has been assumed with a constant COP of 3.1. This is a conservative figure, as there are more efficient units in the market.

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● A flat national average retail energy price of $0.284, obtained by averaging electricity prices from the energyrating.gov.au website.

○ No attempt has been made to increase the price with CPI or to predict the future price of energy.

○ The cost of electricity for heating and cooling is assumed to be the same, where in practice cooling energy may be of higher cost due to charges for peak summer use.

● Correct installation of insulation. ● The total load has been used to calculate the energy cost over a 7 year period. 7 years was

chosen as a reasonable time that a house would be lived in after renovation and before sale. The NatHERS starbands change with climate zone, A 6 star house in Darwin has a much higher total heating or cooling load than the same 6 star house in Brisbane. NatHERS starbands are set by the NatHERS Steering Committee. This change in heating and cooling leads to changes in energy costs vary between the example climates. 7.1.5 Assessment costs Assessing the building for compliance with energy incurs a cost. NatHERS assessments have been costed at $250 each. In the case of the Vic method there are two NatHERS assessments. DtS assessments have been costed at $50. While consultants may charge more than $50 to assess an extension many DtS assessments are done for free by the staff of one of the industry professionals involved in the project such as the builder, designer or building surveyor. $50 has been chosen to reflect the internal cost of providing a DtS assessment of a small extension. 7.1.6 Result selection The two main areas of interest are the:

● Overall energy efficiency of the building as represented by the star rating, reflecting the NCC Performance requirement of the efficient use of energy.

● Total cost over the building lifetime, including both construction and energy used costs, as an indication of the practicality of any proposed change.

A number of possible scenarios will be examined for comparison:

● Existing: The star rating for the existing building before the extension. ● DtS: The general current practice, where the extension meets Elemental DtS and there is no

requirement to change the existing building. ● Victorian method: Calculation of the minimum star rating required in Victoria as outlined in

Part 3.4 of this study. ● Western Australian method, the rating calculated using the Western Australian method, as

outlined in Part 3.5 of this study. ● DTS Upgrade: A possible change to the Elemental DTS requirements where the extension

meets Elemental DtS and the existing part of the building meets Elemental DtS for Roofs NCC, Vol 2 Part 3.12.1.2, by adding ceiling insulation ceiling and Vol 2 Part 3.12.3 Building sealing by adding weather seals.

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7.2 Results Results for the two case studies are presented in Charts 1 - 4, and detailed results are provided in Appendix C. 7.2.1 Case Study Results, Energy Use Charts 1 & 2 show the star ratings for the different assessment methods for case studies 1 & 2. The legend for the charts 1 & 2 is as follows:

● Existing: The star rating for the existing building before the extension. ● DtS: The general current practice, where the existing building is left as is and the extension

meets Elemental DTS. ● Vic Calc: The minimum star rating calculated using the Victorian method, as outlined in Part

3.4 of this study. ● Vic Least cost: The least total cost star rating that achieved above the rating calculated using

the Victorian method. ● WA Calc: The minimum star rating calculated using the Western Australian method. ● WA Least cost: The least total cost star rating that achieved above the rating calculated

using the Western Australian method. ● DtS Upgrade: The extension meets Elemental DtS and the existing building has added

ceiling insulation and weather seals.

In Charts 1 & 2 it can be seen that the DtS option has a very similar star rating to the existing building. Only in Climate 10 - Brisbane for Case Study 1 does the extended building have a lower star rating than the existing building. All of the other options are a substantial improvement. The star rating for Darwin in Chart 2 is zero stars and so doesn’t register on the chart. Generally the improvement is due to the addition of ceiling insulation to the existing ceiling. For all climates but 1 - Darwin. In the NatHERS software hot climates such as Darwin perform better with reflective insulation rather than bulk insulation. Reflective insulation was not considered in the study. There were few results in the 2.5 to 4 star range, the jump being caused by the application of ceiling insulation. Both the WA and Vic calculation methods set a lower star rating minimum than adding insulation to the existing ceiling provides. The Vic & WA Least Cost options are the building specifications which achieved greater than or equal to the calculated star rating at the minimum construction cost.

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Chart 1: Comparison of star ratings - Case Study 1 Large Extension

Chart 2: Comparison of star ratings - Case Study 2 Small Extension

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The legend for the charts 3 & 4: ● DtS: The current base practice, the existing building is left as is and the extension meets

Elemental DtS ● 6 star: The least cost star rating greater than or equal to 6 stars. ● Vic: The least total cost star rating that achieved above the rating calculated using the

Victorian method. ● WA: The least total cost star rating that achieved above the rating calculated using the the

Western Australian method. ● DtS: Upgrade: The extension meets Elemental DtS and the existing part of the building

meets Elemental DtS in the ceiling and has weather seals. Charts 3 & 4 show the total cost for each option and climate. Overall as seen in Charts 1 & 2, the addition of insulation to the ceiling of the existing house reduces the total cost significantly in comparison to the Elemental DtS option. The flexibility allowed by the NatHERS to change roof colour and add ceiling fans can be seen in the difference between the Vic and WA options and the DtS upgrade. Case studies 1 & 2 were chosen for the difference in the size of the extension in relation to the existing building. In cold climates such as 24 - Canberra, 26 - Hobart and 60 – Melbourne, external wall insulation and window changes are often needed to get the building to 6 stars. When the extension is small in relation to the existing building, as in Case study 2, removing and replacing the windows and external wall lining can be cost prohibitive. This can be seen in the high total cost for 6 star ratings for cold climates in Chart 4. In all the climates but one (Darwin), the WA and Vic methods achieve a significant saving on the total cost. The WA method uses one less NatHERS assessment which is the difference between the two.

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Chart 3: Comparison of total cost - Case Study 1 Large Extension

Chart 4: Comparison of total cost - Case Study 2 Small Extension

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8. Proposal for change and alternatives Based on the review and the case studies it is evident that:

● Alterations and additions are not meeting the NCC minimum performance standard. ● There is confusion in the building industry between where, when and how to apply the

current regulations. The intention is to provide a change to the regulation that ensures altered and extended buildings reach a reasonable standard of thermal performance using methods which are simple to apply, are similar to the methods used for new buildings, and there is both an Elemental DtS method and NatHERS method. The logical place for national changes is in the NCC. However the NCC applies to new building work or those parts of the building being effected by the new building work. For work in relation the existing building the NCC defers to state and territory regulations. It is proposed that an amendment is made to the Volume Part 3.12 of NCC or to state and territory regulation that sets a minimum performance standard for the existing part of a building undergoing an alteration or addition. Particularly:

● There is a requirement for the NCC Volume 2 Parts 3.12.1.2 Roofs and 3.12.3 Building sealing to apply to the existing parts of alterations and additions.

● The WA calculation method as is, or simplified, is used to calculate a NatHERS star rating to be applied to the altered or extended building.

In the case where the roof space is inaccessible the applicant can:

● Use another method of compliance, or ● Provide a cost benefit analysis to the building certifier as part of an application for a

concession. As identified in NEEBP Phase One, concessions should be based on cost rather than the building certifiers discretion and an amendment to Part 2.6.1 is required to make this the case.

Clear and simple compliance checklists for alterations and additions should also be developed and used for each stage of the compliance process. These checklists should be automatically generated when using calculation software tools and designed to reduce errors and increase comparability of assessments. 3

3 There are International construction codes that already implement this process to assist with compliance at the planning, construction and completion phases, see https://www.energycodes.gov/sites/default/files/documents/BECP_Building%20Energy%20Codes%20Resource%20Guide%20Code%20Officials_October2010_v00.pdf

https://www.energycodes.gov/sites/default/files/documents/BECP_Building%20Energy%20Codes%20Resource%20Guide%20Code%20Officials_October2010_v00.pdf


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9. Stakeholders Should the proposal for change be acted on, stakeholders likely to be affected are: building certifiers, accredited assessors, builders, designers and homeowners. 9.1 Building certifiers Building certifiers carry the liability that a building they approve for construction meets the NCC. The results of the survey indicated that there is confusion regarding the application of the energy efficiency regulation to alterations and additions. The proposed change would provide clarity allowing the certifiers to be confident of which regulations apply and how the regulation would be applied. 9.2 Accredited assessors Accredited assessors are similar to building certifiers in that there is confusion regarding the appropriate way to assess buildings. While it is hoped that the introduction of the Certificate IV in NatHERS assessment will improve the assessment of alterations and additions, they are currently making assumptions of the features of existing buildings. The WA calculation method provides a way of assessing an existing building dependant on age of the building, removing the need for the assessor to guess. 9.3 Builders and Designers Builders are generally accepting of regulation if the regulation is clear, practical and applies equally to everyone. The current state of the regulation and the ability of building certifiers to provide discretion means the regulation is unclear and the final outcome can depend on the relationship between the builder and the certifier. The proposed changes should make the application of the regulation simpler and clearer. 9.4 Homeowners The case studies show that adding insulation to the existing part of the building can provide a potential saving in heating and cooling bills. While a benefit to the homeowner, this is only one of the potential benefits of a home with greater levels of thermal performance. 9.5 ABCB The ABCB applies only to new building work and relies on the state and territory jurisdictions for the application of the energy efficiency requirements to the existing building. Current ABCB initiatives are for Code consolidation, Variation management and for performance based measures. The proposed changes harmonise the regulations across Australia and provide a performance based measure in the calculation of the adjusted star rating for the extended building.

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10. Proposed regulatory and jurisdictional change The following changes to the jurisdictional regulations are suggested.

Table 4. Treatment of existing dwellings in each State and Territory.

Jurisdiction Current Treatment of Existing Dwellings Proposed Treatment of Existing Dwellings

Federal (NCC) The existing building is not required to comply unless it is subject to new building works.

Make the changes to the NCC as suggested in Part 8 of this report.

ACT If substantial alterations are made to the existing building then the whole building must comply with NCC energy efficiency requirements. Substantial alterations are defined as more than 50% of the volume of the original building, including alterations made during the previous 3 years immediately before the day the application for building approval. The unaltered walls/ roof/ suspended floors of a substantially altered building need not comply if complying would require removal of more than 10% of walls/ roof/ suspended floors, or there is insufficient cavity space to accommodate insulation to achieve the R-value requirement. External glazing to the existing building is required to comply if it is not isolated from the addition. For example, where a living zone is extended onto a kitchen and forms part of the same zone, without doors to separate the zones, the existing kitchen glazing must comply with the Building Code Volume 2, Part 3.12.2.

Remove state based requirement and refer to the NCC, or change state based regulation.

NSW The EP&A Regulation does not have any reference to “Major alterations and/or additions”. “Major alterations and/or additions” can be understood as > 50% volume of the original building (as per ACT and VIC). However, the definition of BASIX-affected Alterations and additions based on

Provide an addition to BASIX requiring the upgrading of insulation to the ceilings and sealing to existing part of extended buildings. It is suggested that this be done in a similar method to the WA calculation and be based on the age of the existing building.

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construction value can apply even if the volume of work is < 50%. With a 4-bedroom house of say 250m2 for example, the addition of another room (say 10% of the original volume) can trigger BASIX requirements when the cost of construction >= $50k.

NT No modifications are required for the existing part of a dwelling unless changing from a Class 10 to a Class 1, in which case compliance is required with all energy efficiency provisions.

NT refers to BCA 2009. Write an amendment for the state and territory variation requiring BCA Volume 2 2009, 3.12.1.2 Roofs and 3.12.3 Building sealing to apply to existing buildings. Or change state based regulation

QLD Where the proposed building work represents more than 50 percent of the existing dwelling’s volume, the building certifier has discretion to apply current building assessment provisions. This discretion can be used when applying relevant energy efficiency requirements under QDC 4.1 for an alteration, addition or relocation.


SA Depending on modifications and compliance method used upgrades to the existing building may be advised.


TAS Existing buildings are not required to be upgraded at the time of alteration and addition works.


VIC Upgrades are not required to the existing building unless the volume of the any new works completed within the previous 3 years represents more than 50 per cent of the volume of the original building, then both the existing and alterations work should comply with the requirements. Where there is access to the roof space ceiling insulation should be installed to the existing building. Similarly, where sealing to the existing building is practical and achievable it should be undertaken.


WA All new building works to comply with NCC Remove state based requirement

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requirements. The existing building is required to comply with the NCC if changing building classification (e.g. Class 10 to Class 1).

and refer to the NCC, or change state based regulation.

11. Good Regulatory Principles The content and questions below have been taken from the ABCB publication “Guideline to preparing a Proposal for Change” which is available for download [link] from the ABCB website. A key objective of the ABCB is to establish building codes and standards that are the minimum necessary to achieve relevant health, safety, amenity and sustainability efficiently. Good regulatory practice requires that any proposed change to the NCC must ensure that: ● There is a rigorously tested rationale for the regulation;

Two case studies are not enough data as a basis for a change in regulation. It is recommended that further work is carried out to provide more evidence.

● The regulation would generate benefits to society greater than the costs (that is, net benefits);

The current case studies show a monetary saving for homeowners which in most jurisdictions is a substantial saving over the current regulation. Using the output of NatHERS to calculate energy use is problematic for the reasons given in this study. Independent corroboration should be undertaken.

● There is no regulatory or non-regulatory alternative (whether under the responsibility of the ABCB

or not) that would generate higher net benefits;

Energy efficiency in Class 1 and Class 10 buildings forms part of the NCC. The proposed change adds a qualification of how existing parts of alterations and additions should be treated rather than being a new regulation. As suggested in the NEEBP Phase One report there is an opportunity at the time that a building is being altered or extended to improve the thermal performance. As with new buildings it would be beneficial to see the industry and homeowners take advantage of the long term benefits offered by improved thermal performance voluntarily. Regulation has been necessary to date.

● The competitive effects of the regulation have been considered and the regulation is no more

restrictive than necessary in the public interest.

The proposed change to the regulation is flexible, allowing participating parties to choose from a number of regulatory paths to achieve compliance.

http://www.abcb.gov.au/Resources/Publications/Consultation/Guideline-to-preparing-a-PFC

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12. Action Plan Actions to be taken include:

● Industry consultation of the recommendations of this study, particularly around the assumed costs used in the case studies and generally around the practicality of changing the regulation.

● There is inconsistency between jurisdictions in what constitutes new building works and subsequently when the NCC requirements apply to alteration and addition works. In order to achieve national consistency in requirements, it is recommended that State and Territory governments work together to reach agreement on a nationally consistent administrative framework for building and plumbing regulations so that the application of the NCC requirements to new building works can be consistently applied.

● Examination of the WA calculation method to see if simplification of the method is possible and examination to make sure there are not climate specific issues which would negatively impact the outcomes for stakeholders.

● Further national case studies on a wider range of buildings and construction types to confirm the findings in this report. Attention should be paid to the glazing calculator and investigations made if changes specific to alterations and additions are required.

● Draft the actual wording of changes to the NCC and the jurisdictional regulations. Relevant other technical documents, such as the NatHERS technical note, be updated.

● Education information for the building industry to be drafted. Particularly continuing professional development (CPD) for Building Certifiers on changing from the practice of granting concessions based on assumption to concessions based on a requested cost analysis.

13. Conclusions A review of the application of NCC energy efficiency requirements for alterations and additions to Class 1 and 10 buildings found that there is confusion and inconsistency in how requirements apply in each jurisdiction throughout Australia. Key issues include:

● The definition of what constitutes an alteration or addition subject to energy performance requirements differs between jurisdictions, from all new building work to numerous exemptions, particularly for an alteration.

● Jurisdictional variation in energy performance requirements centres on building fabric (Part

3.12.1) and glazing (Part 3.12.2), although there is industry confusion about all energy performance requirements.

● All jurisdictions provide additional guidance information and/ or regulatory requirements on

the treatment of alterations and additions resulting in variation from the NCC requirements and each other. Some of the reasons that jurisdictions have developed additional information are due to the NCC not specifically addressing these types of projects and difficulties in applying the NCC requirements to assess alterations and additions projects. Guidance materials are also provided to support application of their own jurisdictional-based assessment methods and protocols.

● Some industry confusion is due to the fact that the jurisdictional guidelines provided by the

states and territories do not always cover every aspect of the NCC in application. For

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example, they may reference DtS (meaning Elemental) and Energy Rating, but not V2.6.2.2. While all NCC assessment methods apply in most jurisdictions, the industry is unaware and confused about these options.

● Across all jurisdictions there is significant industry confusion, including amongst those that

are responsible for interpreting and applying them, about what the requirements are.

● In many jurisdictions certifiers have discretionary powers to determine on a case-by-case basis how energy performance requirements should apply, though they have limited understanding of the relative cost-benefits of their decisions.

● Some jurisdictions are requiring the building to be assessed to a 6 star standard but not

requiring the existing part of the building to be altered, creating the potential for the homeowner to have an incorrect impression of the thermal performance of their home.

● Some jurisdictions regulate assessment methods and compliance requirements based on

the building age, and the volume or floor area subject to alteration and addition works. Case studies conducted to compare the differing compliance methods, show that the addition of ceiling insulation to existing buildings made the largest single improvement in the thermal performance of the building as predicted by NatHERS software. Additionally, cost estimates showed that there was a financial benefit over a 7 year period in insulating the ceiling of the existing building and providing weather stripping. A current method that could be used to assess new buildings for compliance and to counter the identified issues is:

● Using the NatHERS software using the WA method, as is or with alterations, for providing a minimum energy rating which takes into account the age of the existing building and the relative size of the existing building to the alteration.

● Using the Elemental DtS method. It is recommended that the section NCC Vol 2, Part 3.12.1.2 Roofs and 3.12.2 Building Sealing be altered to apply to the existing parts of altered or extended buildings.

● Using clear and simple compliance checklists for alterations and additions that are automatically generated when using calculation software tools, and designed to reduce errors and increase comparability of assessments. These could be based on the Internationals standards4

4 See https://www.energycodes.gov/sites/default/files/documents/BECP_Building%20Energy%20Codes%20Resource%20Guide%20Code%20Officials_October2010_v00.pdf



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10. REFERENCES ● ABCB, 2015. NCC Volume Two Energy Efficiency Provisions 2015 Handbook 2nd Edition. ● ACT Parliamentary Counsel, 2015. Planning and Development Regulation 2008 Replication

No 70 Effective 1 July 2015. ● Australian Bureau of Statistics, 2015. Time Series Workbook 8731.0 Building Approvals,

Australia TABLE 38. Value of Building Approved - Australia. ● Department of Planning, Transport and Infrastructure, 2012. Building Advisory Notice 3/12. ● Energy Efficient Strategies, 2008. Energy Use in the Australian Residential Sector 1986 –

2020. ● Energy Efficient Strategies, 2011. The Value of Ceiling Insulation: Impacts of Retrofitting

Ceiling Insulation to Residential Dwellings in Australia. ● Government of Western Australia Department of Commerce, 2014. WA Alterations &

Additions Protocol for Energy Efficiency in Class 1 or attached Class 10 buildings. ● NSW Government Planning & Infrastructure, 2011. BASIX Guide: Using Simulation for

Alterations and Additions Version 0.4 2 October 2013. ● Northern Territory Government Department of Lands and Planning, 2010. Building Advisory

Services Branch Building Note, Edition Number 68. ● Queensland Government, 2011. Queensland Development Code Mandatory Part 4.1 –

Sustainable Building Guidelines. ● Roberts, N., 2015. Australian Houses are Just Glorified Tents in Winter. The Age, June 11

2015. ● State of Victoria, 2006. Building Regulation 2006 – Reg 608. ● Tasmanian Government, 2013. Building Regulation Advisory Note No. 4. ● Victorian Building Authority (formerly Victorian Building Commission), 2013. 5 and 6 Star

Home Alterations: Characterisation of the Market. ● Victorian Building Authority, 2014. Practice Note 2014-55.

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Appendix A: Case study building plans

Case Study 1

Case Study 2

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Appendix B: Construction Costs Construction costs used to compare energy assessment outcomes are in Tables Appendix B1 & B2. The costs assume that the buildings were finished with internal plasterboard linings and have aluminium framed standard windows. Costs are then estimates for adding insulation and other building products to the existing building and the extension. Costs for building materials vary across the states and territories. Costs used in this study were altered as seen in the tables. Under most current jurisdictions there is no requirement to alter the existing house as it would be an unreasonable cost. Changes to the existing building have been added onto the costs of the new materials as follows:

● Removal and replacement of internal wall linings to the existing house - $49.5 /m2. ● Removal, installation and make good of windows $120 / m2 of window.

The cost for adding insulation to the walls is $49.5 + $7= $56.6. The costs for replacing windows are calculated similarly.

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Table B1: Estimated construction costs($) for Case Study 1 Large Extension

Units Construction Item

cost / m2 or unit VIC NSW QLD SA WA NT ACT TAS

NatHERS Climate 60 28 10 16 13 1 24 26

Each Seals windows doors and exhaust fans to existing 40 42 40 43 40 38 33 39 40

Per m2 Existing Wall R2 56.5 4,734 4,466 4,831 4,509 4,304 3,670 4,383 4,509 Per m2 Existing ceiling R0 0 0 0 0 0 0 0 0 0 Per m2 Existing ceiling R2.5 6 439 414 448 418 399 340 407 418 Per m2 Existing ceiling R4 9 659 621 672 627 599 511 610 627 Per m2 Existing ceiling R5 12 878 828 896 836 798 681 813 836 Per m2 Existing ceiling R6 15 1,098 1,036 1,120 1,045 998 851 1,016 1,045

Per m2 Al frame standard clear glass * 0 0 0 0 0 0 0 0 0

Per m2 Al frame tinted glass 140 1,360 1,283 1,388 1,295 1,236 1,054 1,259 1,295

Per m2 Al frame 5/5/6 Lowe double 370 3,594 3,390 3,667 3,423 3,267 2,786 3,327 3,423

Per m2 Al frame 6.38 Comfortplus neutral 270 2,622 2,474 2,676 2,498 2,384 2,033 2,428 2,498

Per m2 Al frame 6.38 4mm EA Low E 170 1,651 1,558 1,685 1,573 1,501 1,280 1,529 1,573

Each Ceiling fans to existing 75 236 223 241 225 215 183 219 225

Per m2 Addition walls R2 insulation 7 613 579 626 584 558 476 568 584

Per m2 Addition walls R2.5 insulation 10.5 920 868 939 876 837 713 852 876

Per m2 Additional ceiling R2.5 6 406 383 414 387 369 315 376 387 Per m2 Additional ceiling R4 9 609 575 621 580 554 472 564 580 Per m2 Additional ceiling R5 12 812 766 829 773 738 629 752 773 Per m2 Additional ceiling R6 15 1,015 958 1,036 967 923 787 940 967

Per m2 Al frame standard clear glass 0 0 0 0 0 0 0 0 0

Per m2 Al frame tinted glass 20 222 209 226 211 202 172 205 211



Per m2 Al frame 6.38 4mm EA Low E 50 554 523 566 528 504 430 513 528

Per m2 Timb frame DG 4/Ar/4LE 350 3,881 3,661 3,960 3,696 3,528 3,008 3,593 3,696 Each Ceiling fans to existing 75 158 149 161 150 143 122 146 150 Per m2 COSG Waffle R1 2 135 128 138 129 123 105 125 129

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Table B2: Estimated construction costs for Case Study 2 Small Extension

Units Construction Item

cost / m2 or unit VIC NSW QLD SA WA NT ACT TAS

NatHERS Climate 60 28 10 16 13 1 24 26

Each Seals windows doors and exhaust fans to existing 40 42 40 43 40 38 33 39 40

Per m2 Existing Wall R2 56.5 6,784 6,400 6,923 6,461 6,168 5,259 6,282 6,461 Per m2 Existing ceiling R0 0 0 0 0 0 0 0 0 0 Per m2 Existing ceiling R2.5 6 856 807 873 815 778 663 792 815 Per m2 Existing ceiling R4 9 1,283 1,211 1,310 1,222 1,167 995 1,188 1,222 Per m2 Existing ceiling R5 12 1,711 1,614 1,746 1,630 1,556 1,327 1,585 1,630 Per m2 Existing ceiling R6 15 2,139 2,018 2,183 2,037 1,945 1,658 1,981 2,037


Per m2 Al frame tinted glass 140 3,793 3,578 3,870 3,612 3,448 2,940 3,512 3,612



Per m2 Al frame 6.38 4mm EA Low E 170 4,605 4,345 4,699 4,386 4,187 3,570 4,264 4,386

Each Ceiling fans to existing 75 394 372 402 375 358 305 365 375

Per m2 Addition walls R2 insulation 7 100 94 102 95 91 78 93 95

Per m2 Addition walls R2.5 insulation 10.5 150 142 153 143 136 116 139 143

Per m2 Additional ceiling R2.5 6 147 139 150 140 134 114 137 140 Per m2 Additional ceiling R4 9 221 209 226 211 201 171 205 211 Per m2 Additional ceiling R5 12 295 278 301 281 268 229 273 281 Per m2 Additional ceiling R6 15 369 348 376 351 335 286 341 351


Per m2 Al frame tinted glass 20 204 192 208 194 185 158 188 194



Per m2 Al frame 6.38 4mm EA Low E 50 509 480 519 485 463 394 471 485

Per m2 Timb frame DG 4/Ar/4LE 350 3,561 3,360 3,634 3,392 3,237 2,761 3,297 3,392 Each Ceiling fans to existing 75 79 74 80 75 72 61 73 75 Per m2 COSG Waffle R1 2 135 128 138 129 123 105 125 129

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Appendix C: Assessment results and costs for the case studies Headings for tables Climate: Climate zone Seal: Weather seals applied to windows and doors of existing house Wall ins R: R value of insulation added to walls Ceiling ins R: R value of insulation added to ceiling Glazing: Glass and frames, abbreviations for the glass are in Table C1 Fans: Ceiling fans added to Living areas and Bedrooms Roof colour: Colour of the roof of the whole building, 0.3 = Light roof, 0.5 = Medium roof and 0.85 = Dark roof Total load: Total raw heating and cooling load in MJ as estimated by NatHERS software Stars: Star rating from NatHERS software Building: Total cost of building materials added to the building as per the costs set out in Appendix B Energy: Total cost of heating and cooling energy over 7 years Assess: Assessment fee Total: Total cost of building energy and assessment fee PL: Profit or loss against the base case - Existing-as-is and Extension-at-DtS for that climate Table C1 – Glass and glazing used in the study Window abbreviations alstd Aluminium frame standard clear glass al tint Aluminium frame tinted glass al dg low e Aluminium frame 5/5/6 Lowe double al cp Aluminium frame 6.38 Comfortplus neutral al low e Aluminium frame 6.38 4mm EA Low E timb dg low e Timber frame DG 4/Ar/4LE

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Case Study 1 1. Case Study 1 - Exisiting-as-is + Extension-at-DtS

Exisitng Addition Roof

colour Results Costs

Climate Seal

Wall Ins R

Ceiling Ins R Glazing Fans

Wall Ins R


Floor ins

Total load MJ Stars Building Energy Assess Total PL

1 - Dar N R0 R0 alstd N R2.5 R5 alstd N N 0.5 840.9 1 1465 10,389 50 11,904 0 10 - Bris N R0 R0 alstd N R2.5 R5 alstd N N 0.5 268.2 0.7 1928 3,325 50 5,303 0

13 - Per N R0 R0 alstd N R2.5 R5 alstd N N 0.5 395.6 1.3 1101 4,848 50 $5,999.33 0 16 - Ade N R0 R0 alstd N R2.5 R5 alstd N N 0.5 429 1.7 1153 5,264 50 $6,466.91 0 24 - Can N R0 R0 alstd N R2.5 R5 al low e N N 0.5 699.4 1.7 2263 8,727 50 11,040 0 26 - Hob N R0 R0 alstd N R2.5 R5 al low e N N 0.5 600.2 1.9 2328 7,480 50 9,858 0 28 - Syd N R0 R0 alstd N R2.5 R5 alstd N N 0.5 450.5 1.3 1783 5,541 50 7,374 0 60 - Melb N R0 R0 alstd N R2.5 R5 low e N N 0.5 562.7 1.9 2444 6,926 50 9,420 0

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2. Case Study 1 - Least cost 6 star



Climate Seal

Wall Ins R


Wall Ins R


Floor ins


1 - Dar Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.3 376.3 6.1 1163 4,710 250 6,123 -5,781 10 - Bris Y R0 R2.5 alstd Y R2 R2.5 alstd Y N 0.3 48.3 6.2 1772 554 250 2,576 -2,726

13 - Per Y R0 R2.5 alstd N R2 R2.5 al low e Y N 0.3 80.6 6 1868 970 250 3,088 -2,912 16 - Ade Y R0 f R4 alstd N R2 R2.5 al low e Y N 0.3 110 6.1 2166 1,385 250 3,801 -2,666 24 - Can Y R2 R2.5 alstd N R2 R2.5 alstd Y N 0.85 188.2 6.1 5773 2,355 250 8,378 -2,662 26 - Hob Y R2 R2.5 alstd N R2 R2.5 alstd Y N 0.85 179 6 5938 2,216 250 8,404 -1,454 28 - Syd Y R0 f R4 alstd Y R2 R2.5 al low e Y N 0.3 99.1 6.1 2368 1,247 250 3,865 -3,509 60 - Melb Y R2 R2.5 alstd N l R2 R2.5 alstd Y N 0.85 155.9 6.1 6234 1,939 250 8,423 -997

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3. Case Study 1 - Victorian Method



Climate Seal

Wall Ins R


Wall Ins R


Floor ins


1 - Dar Y R0 R0 alstd N R2 R2.5 alstd Y N 0.3 547.3 3.7 823 6,788 500 8,111 -3,794 10 - Bris Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.3 55 5.6 1531 693 500 2,724 -2,579

13 - Per Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.3 86.7 5.7 1364 1,108 500 2,972 -3,027 16 - Ade Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.3 121.4 5.7 1429 1,524 500 3,453 -3,014 24 - Can Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.85 243.7 5.1 1389 3,048 500 4,937 -6,103 26 - Hob Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.85 232.4 5.1 1429 2,909 500 4,838 -5,020 28 - Syd Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.3 111.7 5.6 1415 1,385 500 3,300 -4,074 60 - Melb Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.85 202 5.2 1500 2,493 500 4,493 -4,927

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4. Case Study 1 - WA Method



Climate Seal

Wall Ins R


Wall Ins R


Floor ins


1 - Dar Y R0 R0 alstd Y R2 R2.5 alstd Y N 0.3 531.3 3.9 1006 6,649 250 7,905 -3,999 10 - Bris Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.3 55 5.6 1531 693 250 2,474 -2,829

13 - Per Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.3 86.7 5.7 1364 1,108 250 2,722 -3,277 16 - Ade Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.3 121.4 5.7 1429 1,524 250 3,203 -3,264 24 - Can Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.85 243.7 5.1 1389 3,048 250 4,687 -6,353 26 - Hob Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.85 232.4 5.1 1429 2,909 250 4,588 -5,270 28 - Syd Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.3 111.7 5.6 1415 1,385 250 3,050 -4,324 60 - Melb Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.85 202 5.2 1500 2,493 250 4,243 -5,177

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5. Case Study 1 - Upgrade - Ext at DtS - upgrade ceiling insulation R5 and seal



Climate Seal

Wall Ins R


Wall Ins R


Floor ins


1 - Dar Y R0 R5 alstd N R2.5 R5 alstd N N 0.5 384.5 5.9 2178 4,710 50 6,938 -4,966 10 - Bris Y R0 R5 alstd N R2.5 R5 alstd N N 0.5 59.2 5.3 2867 693 50 3,610 -1,693 16 - Ade Y R0 R5 alstd N R2.5 R5 alstd N N 0.5 85.5 5.8 2554 1,108 50 3,712 -2,755

13 - Per Y R0 R5 alstd N R2.5 R5 alstd N N 0.5 118.4 5.8 2676 1,524 50 4,250 -1,750 24 - Can Y R0 R5 alstd N R2.5 R5 al low e N N 0.5 234.3 5.3 3115 2,909 50 6,074 -4,966 26 - Hob Y R0 R5 alstd N R2.5 R5 al low e N N 0.5 229.9 5.1 3204 2,909 50 6,163 -3,695 28 - Syd Y R0 R5 alstd N R2.5 R5 alstd N N 0.5 110.6 5.6 2651 1,385 50 4,086 -3,288 60 - Melb Y R0 R5 alstd N R2.5 R5 al low e N N 0.5 192.6 5.4 3364 2,355 50 5,769 -3,651

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Case Study 2 1. Case Study 2 - Exisiting-as-is + Extension-at-DtS



Climate Seal

Wall Ins R


Wall Ins R


Floor ins


1 - Dar N R0 R0 alstd N R2.5 R5 timb dg

lowe N N 0.5 863 0.6 3166 10,666 50 13,882 0 10 - Bris N R0 R0 alstd N R2.5 R5

timb dg lowe N N 0.5 256.2 0.6 4168 3,186 50 7,404 0

13 - Per N R0 R0 alstd N R2.5 R5 alstd N N 0.5 495.3 1.1 499 6,095 50 6,644 0 16 - Ade N R0 R0 alstd N R2.5 R5 alstd N N 0.5 452 0.8 476 5,541 50 6,067 0 24 - Can N R0 R0 alstd N R2.5 R5 al low e N N 0.5 784.1 1.2 956 9,697 50 10,703 0 26 - Hob N R0 R0 alstd N R2.5 R5 al low e N N 0.5 676.3 1.4 983 8,450 50 9,483 0 28 - Syd N R0 R0 alstd N R2.5 R5 alstd N N 0.5 504.7 0.9 494 6,234 50 6,778 0 60 - Melb N R0 R0 alstd N R2.5 R5 alstd N N 0.5 649.1 1.3 524 8,034 50 8,608 0

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1. Case Study 2 Least cost 6 star



Climate Seal

Wall Ins R


Wall Ins R


Floor ins


1 - Dar Y R2 R2.5 alstd Y R2 R2.5 timb sg

lowe Y N 0.3 364 6 9213 4,571 250 14,034 152 10 - Bris Y R2 R4 alstd Y R2 R2.5

timb sg lowe Y N 0.3 46.9 6 12563 554 250 13,367 5,963

13 - Per Y R2 R4 alstd N R2 R2.5 timb sg

lowe Y N 0.3 75.7 6 10835 970 250 12,055 5,411 16 - Ade Y R2 R4 alstd N R2 R2.5

timb sg lowe Y N 0.3 101.9 6.1 11351 1,247 250 12,848 6,781

24 - Can Y R2 R6 dg lowe N R2 R6

timb sg lowe Y N 0.85 181.3 6 21313 2,216 250 23,779 13,077

26 - Hob Y R2 R6 dg lowe N R2 R5

timb sg lowe Y N 0.85 176.1 5.9 21852 2,216 250 24,318 14,835

28 - Syd Y R2 R4 alstd Y R2.5 R2.5

timb sg lowe Y N 0.3 95.2 6 11662 1,247 250 13,159 6,381

60 - Melb Y R2 R6 al cp Y R2.5 R5

timb sg lowe Y N 0.85 152.5 6 20679 1,939 250 22,868 14,260

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2. Case Study 2 Victorian Method

Climate Seal

Wall Ins R


Wall Ins R


Floor ins


1 - Dar Y R0 f R0 alstd N R2 R2.5 alstd Y N 0.3 706.1 1.7 224 8,727 500 9,451 -4,431 10 - Bris Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.3 93.5 3.4 1168 1,108 500 2,776 -4,628

13 - Per Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.3 144.8 3.6 1041 1,801 500 3,342 -3,302 16 - Ade Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.3 184 3.9 1090 2,216 500 3,806 -2,261 24 - Can Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.85 318.6 3.9 1060 4,017 500 5,577 -5,125 26 - Hob Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.85 292.6 3.9 1090 3,602 500 5,192 -4,291 28 - Syd Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.3 184.2 3.5 1080 2,355 500 3,935 -2,843 60 - Melb Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.85 261.6 4 1145 3,186 500 4,831 -3,777

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4. Case Study 2 -WA Method



Climate Seal

Wall Ins R


Wall Ins R


Floor ins


1 - Dar Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.3 473.2 4.4 888 5,818 250 6,956 -6,926 10 - Bris Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.3 93.5 3.4 1168 1,108 250 2,526 -4,878

13 - Per Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.3 144.8 3.6 1041 1,801 250 3,092 -3,552 16 - Ade Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.3 184 3.9 1090 2,216 250 3,556 -2,511 24 - Can Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.85 318.6 3.9 1060 4,017 250 5,327 -5,375 26 - Hob Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.85 292.6 3.9 1090 3,602 250 4,942 -4,541 28 - Syd Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.3 184.2 3.5 1080 2,355 250 3,685 -3,093 60 - Melb Y R0 R2.5 alstd N R2 R2.5 alstd Y N 0.85 261.6 4 1145 3,186 250 4,581 -4,027

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Case Study 2 - Upgrade - Ext at DtS - upgrade ceiling insulation R5 and seal



Climate Seal

Wall Ins R


Wall Ins R


Floor ins


1 - Dar Y R0 R5 alstd N R2.5 R5 timb sg

lowe N N 0.5 408.2 5.3 4525 5,125 50 9,700 -4,182 10 - Bris Y R0 R5 alstd N R2.5 R5

timb sg lowe N N 0.5 71.6 4.3 5957 831 50 6,838 -566

13 - Per Y R0 R5 alstd N R2.5 R5 alstd N N 0.5 172.2 4.1 2168 2,078 50 4,296 -2,348 16 - Ade Y R0 R5 alstd N R2.5 R5 alstd N N 0.5 136.4 3.8 2070 1,662 50 3,782 -2,285 24 - Can Y R0 R5 alstd N R2.5 R5 al low e N N 0.5 307.2 4 2579 3,879 50 6,508 -4,195 26 - Hob Y R0 R5 alstd N R2.5 R5 a; low e N N 0.5 291.4 3.9 2653 3,602 50 6,305 -3,178 28 - Syd Y R0 R5 alstd N R2.5 R5 alstd N N 0.5 173.0 3.7 2148 2,216 50 4,414 -2,363 60 - Melb Y R0 R5 alstd N R2.5 R5 alstd N N 0.5 263.0 4 2277 3,325 50 5,652 -2,957

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Appendix D: Online Surveys of Two Key Industry Groups: Certifiers & Energy Assessors ONLINE SURVEYS OF TWO KEY INDUSTRY GROUPS – CERTIFIERS & ENERGY ASSESSORS Introduction Building certifiers and energy efficiency assessor play a key role in interpreting and applying building energy efficiency requirements for the building industry. To gain insights into their experiences in interpreting and applying the energy efficiency requirements to Class 1 and 10 alteration and addition projects, feedback was gathered from these two focal groups using an online survey. Methodology Two related online survey were used to gather information from the two industry groups in all jurisdictions:

• Group One – Private and council certifiers; • Group Two – Energy efficiency assessors.

The surveys were hosted by kwiksurveys, and were open for submission in April 2015. Survey participants were contacted directly and invited to participate by Sustainability House, as well as with the support of several organisations:

• Australian Institute of Building Surveyors • Association of Building Sustainability Assessors • Building Design Association of Victoria • Daniel Ellis-Jones – Department of Commerce (WA) • Natasha Palich – Council Alliance for a Sustainable Built Environment (VIC) • Steve Storer – Department of Housing and Public Works (QLD) • Wayne Gorman – Consulting Plus • Sally Modystach - Healthy Environs.

The survey questions are included in the results section, together with the summaries of responses. Results In total survey responses were received from 50 certifiers (Figure 1) and 86 energy assessors (Figure 11), with responses from at least one certifier and one energy assessor in each jurisdiction. Results are in attached pdf files